Could this gator’s teeth hold clues for regenerating humans’ pearly whites? Photo by Flickr user montuschi

Humans drew the short end of the toothbrush when it comes to our pearly whites’ longevity. Other animals such as reptiles and fish frequently lose and replace their teeth by growing new ones, but people are stuck with the same set of mature adult teeth their entire lives. If they lose a tooth–or all 32–dentures are usually the only option.

Oddly enough, alligators’ deadly chomps may hold a clue for how scientists could coax humans into regrowing teeth. These reptiles belong to the order Crocodilia, who, with their famous cheerful grins, caused songwriters to warn that you should never smile at a crocodile. To the bane of Captain Hook and other victims of gator and croc attacks, the large reptiles often regrow their razor teeth multiple times. Researchers think that, given time, technology may advance so that we can borrow these reptilian smiles. But first, scientists need to understand just how these animals keep their smiles toothy.

In a paper published this week in the Proceedings of the National Academy of Sciences, an international team of researchers attempted to get at the mechanisms behind the superior tooth regenerating abilities of one species of Crocodilia–the American alligator–in the hopes of applying the results to humans.

In humans, organs such as hair, scales, nails and teeth “are at the interface between an organism and its external environment and therefore, face constant wear and tear,” the researchers write. But alligators have evolved ways to deal with these challenges. The carnivores can replace any of their 80 teeth up to 50 times throughout their 35 to 75-year lives. Small replacement teeth grow under each mature alligator tooth, ready to spring into action the moment a gator loses a tooth.

To figure out the molecules and cells responsible for replacement, the researchers used X-rays and small tissue samples from alligator embryos, hatchlings and 3-year old juveniles’ developing teeth. They also grew tooth cells in the laboratory and created computer models of the process. Alligator teeth appear to cycle continuously, they write, but in fact the animals’ teeth seem to go through three distinct phases: pre-initiation, initiation and growth.

Once an alligator loses a tooth, these three phases kick off. The dental lamina, or a band of tissue associated with the initial stages of tooth formation in many animals, begins to bulge. This triggers stem cells and an array of signaling molecules that direct the process of forming a new tooth.

These results may be applicable to humans’ pearly whites. Alligators’ flesh-chomping incisors are surprisingly similar to well-organized, complex vertebrate teeth such as ours. In humans, a remnant of the dental lamina–the structure crucial to tooth formation–still exists and sometimes wrongly activates and begins forming toothy tumors. If the researchers could better tease out the molecular signaling pathways behind alligator tooth replacement, they reason, they they may be able to induce those same chemical instructions in humans to coax the body into forming a new tooth after one gets kicked out in a soccer game or has to be removed after becoming infected.

Alternatively, doctors may be able to shut off the molecules responsible for conditions that cause uncontrolled tooth formation. Individuals suffering from cleidocranial dysplasia syndrome grow many unusually shaped, peg-like teeth, for example, and people with Gardner syndrome also grow supernumerary, or extra, teeth.

While the researchers still need to clarify more molecular details behind alligator tooth growth, this initial study does hint that doctors and dentists may someday be able to selectively bestow patients with the reptiles’ tooth-regenerating abilities.

“Based on our study, it may be possible to identify the regulatory network for tooth cycling,” the researchers conclude. “This knowledge will enable us to either arouse latent stem cells in the human dental lamina remnant to restart a normal renewal process in adults who have lost teeth or stop uncontrolled tooth generation in patients with supernumerary teeth.”

Either way, they note that “Nature is a rich resource from which to learn how to engineer stem cells for application to regenerative medicine.”

Helpless babe or capable professional navigator? Photo by Samuel Blanc

With their big, glossy black eyes and downy fluff, baby Weddell seal pups are some of the most adorable newborns in the animal kingdom. But these cute infants are far from helpless bundles of joy. New research published in the journal Marine Mammal Science reveals that Weddell seal pups likely possess the most adult-like brain of any mammal at birth.

The seal pups’ brains, compared to adult seals’ brain proportions, are the largest known for any mammal to date. The researchers write that this is “remarkable” considering that the pups are quite small at birth compared to many other newborn mammals.

To arrive at these findings, a team of researchers from the Smithsonian Environmental Research Center and the National Museum of Natural History traveled to Antarctica to collect fresh pups specimens. They took advantage of the fact that many pups never make it to adulthood due to stillbirths, abandonment and accidental death, such as being crushed by an adult. The researchers collected 10 dead seal pups (which quickly freeze in the Antarctic temperatures), conducted a few measurements and then decapitated and shipped the frozen heads back to the Smithsonian. They also tossed in a couple adult Weddell seal heads into the mix, one of which had died from acute toxemia–possibly from its gut being punctured by a fish spine–and the other whose cause of death could not be determined.

Back in the U.S., the researchers partially thawed the skulls in a lab and–like a well picked-over Thanksgiving turkey–manually peeled the tissue off of the baby seal faces. Then, they drilled into the skulls to extract the intact brains. Finally, they put the bones into a tank full of flesh-eating beetles to remove any remaining scraps of meat. Clean skulls and brains in hand, they went about taking measurements, and they also drew upon measurements of some older Weddell Seal skull specimens from the museum’s collection.

Remarkably, baby Weddell seal brains are already 70 percent developed at birth, the team found. Compare this to human infants, whose brains are a mere 25 percent of their eventual adult mass. As a Smithsonian statement explains, baby animals born with proportionally larger brains usually live in challenging environments in which they need to act quickly in order to survive. Other animals that share this trait include most marine mammals, zebras and wildebeest.

For Weddell seal pups, large brains likely help with diving under ice sheets and orienting themselves under water at less than three weeks old–an extremely dangerous task for any mammal, newborn or not. The pups must acclimate quickly since Weddell seal mothers abandon their young at about 6 weeks old, meaning they need to be able to completely fend for themselves when that day arrives.

In nature, however, everything comes with a price. The Weddell seal pups may have the biggest, best developed brains on the block when compared to what they will be as adults, but this metabolically taxing organ requires excessive energy to maintain. A pup weighing just 65 pounds needs between 30 to 50 grams of glucose per day in order to survive, and the team estimates that the energetically hungry brain may account for a full 28 grams of that demand. 

Luckily for the seal pups, their mothers’ milk is almost exactly matched to the babies’ caloric needs. Weddell seal milk supplies about 39 grams of sugar per day. Females seals, however, lose significant weight while tending to their young, which jeopardizes their own survival. At their mother’s cost, the babies’ brains are allowed to thrive. That is, until their mother decides she’s had enough with the nurturing and leaves her pups to survive on their own.   

How many unborn brothers and sisters did this sand tiger shark devour to be here today? Photo by Amada44

Baby animals may seem irresistibly adorable, but in reality many of them are calculating killers. Hyena, wolf or even dog litter runts are pushed aside by their larger siblings and left to go hungry; fuzzy white egret chicks will kick their weaker clutch mates out of the nest to certain doom; and  baby golden eagles sometimes go so far as to snack on their smaller brothers and sisters while their mother looks on.

Perhaps most disturbing of all, however, is the case of the baby sand tiger shark. While sharks may not be the most snuggly animals to begin with, the sand tiger shark sets a new precedent for fratricide. This species practices a form of sibling-killing called intrauterine cannibalization. Yes, “intrauterine” refers to embryos in the uterus. Sand tiger sharks eat their brothers and sisters while still in the womb.

Even by nature’s cruel standards, scientists admit that this is an unusual mode of survival. When sand tiger sharks develop in their mother’s uteri (females have both a left and right uterus), some–usually the embryo that hatched first from its encapsulated, fertilized egg–inevitably grow faster and larger than others. Once the largest embryos cross a certain size threshold, the hungry babies turn to their smaller siblings as convenient meals. “The approximately 100 mm hatchling proceeds to attack, kill and eventually consume all of its younger siblings, achieving exponential growth over this period,” a team of researchers who investigated the phenomenon wrote this week in Biology Letters.  

Size differential between a recent hatchling (H) and an older embryo (E) from the same uterus in a typical litter the researchers samples. Photo by Chapman et al., Biology Letters

From what began as two uteri full of a dozen embryos results in just two dominating baby sand tiger sharks coming full term. What’s more, once the unborn babies consume all of the living embryos, they turn to their mother’s unfertilized eggs next, in a phenomenon called oophagy, or egg-eating. By the time those two surviving babies are finally ready to be introduced into the big, bright world, all of the pre-birth inner feasting has paid off. They emerge from their mother measuring in at about 95 to 125 centimeters long, or a bit longer than a baseball bat, meaning fewer predators can pick them off than if they had shared food with siblings and were smaller.   

This peculiar situation has implications for the genetic makeup of the species. Female sand tiger sharks, like many animals, mate with multiple males. Oftentimes in nature, females determine which males will sire the next generation by selectively choosing to mate with the most impressive bachelor (or bachelors) around. If mating with multiple males at any given time–as sharks, insects, dogs, cats and many other animals sometimes do–the babies that the female eventually produces share the same womb with siblings that may have different fathers. 

In this case, however, there are two modes of selection at work. Females may choose mates, but that does not guarantee those males’ genes will make the cut. The embryos the males sire will also have to survive the subsequent frenzy of cannibalism going on inside the female’s body. 

To find out whether some males are mating but missing out on actually producing offspring, the authors of this new study undertook microsatellite DNA profiling of 15 sand tiger shark mothers and their offspring. The researchers collected the sharks from accidental mortality events near protected beaches in South Africa between 2007 to 2012. By comparing the embryo genetics, the researchers could determine how many fathers were involved in fertilizing the eggs.

Nine of the females, or 60 percent, had mated with more than one male, the researchers found. When it came to which embryos hatched and grew large first (and thus would have survived if their mothers hadn’t have been killed), 60 percent shared the same father. This means that even if a female mates with more than one male, there is no guarantee that the male has been successful in passing on his genes. Rather, he could have just provided a convenient entree for another male’s offspring.

This also explains some male sand tiger shark behavior and physiology. Male sand tiger sharks often guard their mates against other males just after copulation. Males of this species also produce a conspicuously large amount of sperm compared to other sharks. Both of these characteristics increase the likelihood that the embryo fertilized by that male will successfully implant in the female’s uterus earlier, giving it a significant head start for developing more quickly than its siblings, which makes it more likely that the recent mate’s offspring will eat the others that may come along.

As for the females sand tiger sharks, some researchers think they actually may not have much of a choice when it comes to mating with multiple males.  It could be that females just give in to some amorous partners because the energetic cost of resisting those advances outweighs the cost of just conceding to the act–a behavior biologists call the convenience polyandry hypothesis. In this case, however, females may still get the final laugh since the males they first mated with and most likely preferred will have the greater chance of actually triumphing as the father of their children. “[Embryonic cannibalism] may allow female sand tigers to engage in convenience polyandry after mating with preferred males without actually investing in embryos from these superfluous copulations,” the researchers speculate.

While the females did invest in initially developing those doomed embryos, those investments are much smaller than what would be required to bring multiple embryos to full term. Those smaller embryos also represent resources allocated to the stronger, dominate embryonic winners, which thus have a better chance of surviving and passing on their mother’s genes than if she had spent the energy to instead birth multiple, weakling babies. In a way, the mother shark is providing nourishment for her strongest babies by producing multiple embryos that the most robust can eat. 

“This system highlights that competition and sexual selection can still occur after fertilization,” the authors write. For example, the first embryo to implant may not end up being the the one that survives the gladiator arena of the sharks uterus. While this new research still needs to delve into the details of the competition that takes place within the uterus, a picture is emerging based upon these initial findings: Females may chose which males to mate with or may be coerced into reluctantly mating, but male sperm fitness and the quality of the embryos they produce could also carry significant weight in which animals ultimately wind up as winners in this system. 

“This competition can play an important and probably under-appreciated role in determining male fitness,” the authors conclude. 

A baby cao vit gibbon learns to search for food. Photo: Zhao Chao 赵超, Fauna and Flora International

You probably haven’t heard of the world’s second rarest ape, the cao vit gibbon. Scientists know of only one place the species still lives in the wild. In the 1960s, things got so bad for the cao vit gibbon that the species was declared extinct. But in 2002, to the surprise and elation of conservationists, the animals—whose shaggy coats can be a fiery orange or jet black—turned up along Vietnam’s remote northern border. Several years later, a few gibbons were found in China, too.

Also known as the eastern black-crested gibbon, the cao vit gibbons once covered an expanse of forest spanning from southern China and northern Vietnam just east of the Red River, but today only about 110 individuals survive. This gibbon is highly inclined to stick to the trees—in a previous study, during more than 2,000 hours spent observing gibbons in the field, researchers saw only once and very briefly one young male cao vit gibbon come down from the canopy and walk on a rock for a few seconds. Population surveys based on watching the animals in the branches reveal that the gibbons live in 18 groups scattered throughout the area. That makes it the second least populous species of ape, just after the Hainan gibbon, another type of extremely rare gibbon living in the same area of Asia.

In 2007 and 2009, Vietnam and then China hustled to establish special protected areas dedicated to preventing the cao vit gibbon’s extinction. Much of the area surrounding the remaining populations of gibbons is quickly being converted to agricultural fields and pasturesor cut down to make charcoal to sell and use at home, a common practice in the area. Hunting—though illegal—is also an issue, as exotic wild meat dinners are popular with locals in the region.

For an endangered species to recover rather than just survive, it needs to grow in numbers. But any given patch of land can only support so many animals given the amount of food and space that’s available. If populations exceed this threshold—called a carrying capacity—then animals will either starve, get picked off by predators or have to move somewhere else. 

Researchers from Dali University in Yunnan, the Chinese Academy of Sciences in Kunming and the Chinese Research Academy of Environmental Sciences in Beijing wanted to find out how much of the protected forest the cao vit gibbons had expanded into, and also how many animals that pocket of land could eventually support. To answer this question, they turned to high-resolution satellite images, describing their results in the journal Biological Conservation.

Once they acquired aerial images of the gibbons’ habitat, they classified it into forest, scrub, shrub land and developed areas. This was important because gibbons can only live high in forest canopies, meaning the latter three categories were out of bounds for potentially supporting the animals. Overall, the area could be divided into five different zones that were split apart by either roads or rivers. From there, the researchers plugged the data into computer models that ranked possible gibbon habitat from high to low quality.

Habitat quality over the five zones the researchers identified. Stars mark sites where gibbons currently live. Image from Fan et al., Biological Conservation

Their results revealed several bits of news, some good and some bad. First, from the models it seems that 20 groups of gibbons could eventually live in the protected forest areas before the population reaches its carrying capacity threshold. However, as human development creeps closer and closer, that disturbance could lower that figure. As things stand, the gibbons will likely reach their carrying capacity in the current habitat in 15 years, which doesn’t bode well for building up the species’ numbers.

There are a couple options. The protected area isn’t all great habitat, it turns out. Some of it is just mediocre for gibbons. If that span of forest could be improved, it could eventually support up to 26 groups of animals. The researchers also identified two other potential areas where gibbons could live if they could somehow manage to travel there (no gibbon has ever been known to cross a river or a road). But these patches of welcoming forest, located in Vietnam, are not protected, so they likely will not remain forests for long. If the government decided to protect those areas, the researchers write, they could serve as places for cao vit gibbons to live in the future, especially if narrow corridors of trees connecting the two areas were protected and restored as well.

If these patches of forest were protected, gibbons would not be the only species to benefit. Numerous other species of primates and monkeys, civets, pangolins, porcupines, birds, bats and many more depend upon those last remaining jungle habitats for survival. “In summary, the last remaining population of cao vit gibbon is nearing its carrying capacity in the current remaining forest patch,” the authors write. “Forest protection and active forest restoration using important food tree plantings to increase habitat quality and connectivity should be the most critical part of the ongoing conservation management strategy.”

This chimp may look innocent, but he may harbor any of dozens of diseases that infect humans. Photo by AfrikaForce

Anyone who has read a Richard Preston book, such as The Hot Zone or Panic in Level 4, knows the danger of tampering with wildlife. The story usually goes something like this: Intrepid explorers venture into a dark, bat infested cave in the heart of East Africa, only to encounter something unseen and living, which takes up residence in their bodies. Unknowingly infected, the happy travelers jump on a plane back to Europe or the States, spreading their deadly pathogen willy-nilly to every human they encounter upon the way. Those people, in turn, bring the novel virus or bacterium back home to strangers and loved ones alike. Before the world knows it, a pandemic has arrived.

This scenario may sound like fiction, but it’s exactly what infectious disease experts fear most. Most emerging infectious diseases in humans have indeed arisen from animals–think swine and bird flu (poultry and wild birds), SARS (unknown animals in Chinese markets), Ebola (probably bats) and HIV (non-human primates). Therefore, experts prioritize the task of figuring out which animals in which regions of the world are most prone to delivering the latest novel pathogen to hapless humanity.

With this in mind, researchers at Harvard University, the University of Granada and the University of Valencia set out to develop a new strategy for predicting the risk and rise of new diseases transmitted from animals before they happen, describing their efforts in the journal Proceedings of the National Academy of Sciences.

To narrow the hypothetical disease search down, the team chose to focus on non-human primates. Because monkeys and great apes are so closely related to us, their potential for developing and transmitting a pathogen suited to the human body is greater than the equivalent risk from animals such as birds or pigs. As a general rule, the more related species are, the greater the chances they can share a disease. The researchers gathered data from 140 species of primates. They overlaid that information with more than 6,000 infection records from those various primate species, representing 300 different pathogens, including viruses, bacteria, parasitic worms, protozoa, insects and fungus. This way, they could visualize which pathogens infect which species and where.

Like mapping links between who-knows-who in a social network, primates that shared pathogens were connected. This meant that the more pathogens an animal shared with other species, the more centrally located it was on the tangled web of the disease diagram.    

A diagram depicting shared parasites among primate species. Each bubble represents one species, with lines connecting species by shared pathogens. The larger the bubble, the more emerging infectious diseases that species harbors. The dark blue bubbles represent the top 10 primates that share the most emerging infectious diseases with humans. Photo by Gomez et al., via PNAS

From studying these charts, a few commonalities emerged. Animals at the center of the diagram tended to be those that lived in dense social groups and also covered a wide geographic range (yes, similar to humans). These species also tended to harbor parasites that are known to infect humans, including more pathogens identified as emerging infectious diseases. In other words, those species that occurred in the center of the diagram are the best positioned to kick off the next pandemic or horrific infectious disease, and thus should be the ones that experts should keep the closest watch on.

Such animals could qualify as “superspreaders,” or those that receive and transmit pathogens very often to other species.”The identification of species that behave as superspreaders is crucial for developing surveillance protocols and interventions aimed at preventing future disease emergence in human populations,” the authors write.

Apes appeared in the heart of the disease diagram and are among the species we should be most worried about, which is not surprising considering that diseases such as malaria and HIV first emerged from these animals. On the other hand, some non-ape primates, including baboons and vervet monkeys, also popped up in the center of the diagram and turn out to harbor many human emerging disease parasites. 

Currently, our ability to predict where, when and how new emerging infectious diseases might arise is “remarkably weak,” they continue, but if we can identify those sources before they become a problem we could prevent a potential health disaster on a regional or even global scale. This new approach for identifying animal risks, the authors write, could also be applied to other wildlife groups, such as rodents, bats, livestock and carnivores. “Our findings suggest that centrality may help to detect risks that might otherwise go unnoticed, and thus to predict disease emergence in advance of outbreaks—an important goal for stemming future zoonotic disease risks,” they conclude. 

This adult male bedbug wants to suck your blood. Photo: Armed Forces Pest Management Board

For thousands of years, humans have shared their beds with blood-sucking parasites. The ancient Greeks complained of bedbugs, as did the Romans. When the lights go off for those suffering from this parasitic infestation today, from under the mattress or behind the bedboard creeps up to 150,000 of the rice grain-sized insects (though average infestations are around 100 insects). While bedbugs are one of the few parasites that live closely with humans yet do not transmit a serious disease, they do cause nasty red rashes in some of their victims, not to mention the psychological terror of knowing that your body becomes a buffet for crawling bloodsuckers after dark. 

By the 1940s this age-old parasite was mostly eradicated from homes and hotels in the developing world. But around 1995, the bedbug tides again turned. Infestations began flaring up with a vengeance. Pest managers and scientists aren’t sure what happened, exactly, but it may have been a combination of people traveling more and thus increasing their chances of encountering bedbugs in run down motels or infested apartments; of bedbugs bolstering their resistance to common pesticides; and of people simply letting their guard down against the now unfamiliar parasites.

Large cities such as New York have particularly suffered from this resurgence. Since 2000, the New York Times has run dozens of articles documenting the ongoing plague of bedbugs, with headlines such as Even Health Dept. Isn’t Safe from Bedbugs and Bringing Your Own Plastic Seat Cover to the Movies.

As many hapless New Yorkers have found, detecting stealthy bedbugs is only the first step of what usually turns into a long, desperate eradication battle.  Most people have to combine both pesticides and non-chemical methods for purging their apartments. In addition to dousing the apartment and its contents in pesticides, this includes throwing away all furniture the bugs are living on (streetside mattresses in NYC with a “BEDBUGS!” warning scrawled across them are not an out-of-the-ordinary sight), physically removing the bodies of poisoned bugs, subjecting the home to extreme heat or cold, or even hiring a bedbug sniffing dog. Sometimes, after so many sleepless nights and days spent meticulously combing the cracks between the mattress and sheets or searching behind couch cushions, residents simply throw up their hands, move out and start their lives over.

Recognizing this ongoing problem, researchers are constantly trying to come up with new methods for quickly and efficiently killing the pests. The latest technique, described today in the Journal of the Royal Society Interface, takes a hint from mother nature and history. For years, people in Eastern Europe’s Balkan region have known that kidney bean leaves trap bedbugs, sort of like a natural fly paper. In the past, those suffering from infestations would scatter the leaves on the floor surrounding their bed, then collect the bedbug-laden greenery in the morning and destroy it. In 1943, a group of researchers studied this phenomenon and attributed it to microscopic plant hairs called trichomes that grow on the leaves’ surface to entangling bed bug legs. They wrote up their findings in “The action of bean leaves against the bedbug,” but World War II distracted from the paper and they wound up receiving little attention for their work.

Rediscovering this forgotten research gem, scientists from the University of California, Irvine, and the University of Kentucky set out to more precisely document how the beans create this natural bedbug trap and, potentially, how it could be used to improve bedbug purging efforts. “We were motivated to identify the essential features of the capture mechanics of bean leaves to guide the design and fabrication of biomimetic surfaces [or synthetic materials that mimic ones found in nature] for bed bug trapping,” they write in their paper.  

Images of bed bug legs (yellow) on bean leaf surfaces with hooked trichomes (green). Scanning electron microscope photo from The Royal Society

They used a scanning electron microscope and video to visualize how the trichomes on the leaves stop the bedbugs in their ravenous tracks. Rather than a Velcro-like entanglement as the 1943 authors had suggested, it seems that the leaves stick into the insects’ feet like giant thorns, physically impaling the pests.

Knowing this, the researchers wondered if they could improve upon the method as a way to treat bedbug infestations, because leaves themselves dry out and can’t be scaled up to larger sizes. “This physical entrapment is a source of inspiration in the development of new and sustainable [or scalable and chemical-free] methods to control the burgeoning numbers of bed bugs,” they write.

They used fresh bean leaves as a template for micro-fabricating produced surfaces that precisely mimicked the leaves. To do this, they created a negative molding of the leaves, then poured in polymers sharing a similar material composition of the living plant’s cell walls.

Fabrication of biomimetic surfaces (d and e) from bean leaves (b and c). (1–3) A negative molding material is poured onto a leaf surface, and pressure is applied. (4–6) The leaf is removed, and the negative mold is filled with the positive replica material. (7) The negative mold is removed leaving the replica. Image from The Royal Society

The team then allowed bedbugs to walk across their synthetic leaves to test their effectiveness compared to the real deal. The fabricated leaves did snag the bugs, but they didn’t hinder the insects’ movements quite as effectively as the living plants. But the researchers are not deterred by these initial results. They plan to continue working on the problem and improving their product by more precisely incorporating the mechanical properties of the living trichomes. The optimistically conclude: 

With bed bug populations skyrocketing throughout the world, and resistance to pesticides widespread, bioinspired microfabrication techniques have the potential to harness the bed bug-entrapping power of natural leaf surfaces using purely physical means.

A handsome tokay gecko. Photo: Ethan Knapp and Alyssa Stark

Anyone who lives in or has visited a tropical country is likely familiar with the chipper chirping of the gecko. These friendly little lizards inhabit homes and jungles stretching from Indonesia to Tanzania to the Dominican Republic. They emerge after sunset, taking advantage of their night vision eyesight—which is 350 times more powerful than a human’s—and are welcome guests in homes and hotels since they gobble up mosquitoes and other insect pests.

In addition to the locals, scientists also love these colorful lizards. Geckos possess the unique ability among lizards to run up flat walls and scamper across ceilings, even if the surface is very smooth. Researchers have been puzzling over this ability for years, and dozens of labs have tested gecko adhesion in the hopes of harnessing this superpower for potential use in everything from robotics to space technology to medicine to “gecko tape.”

Gecko toes, it turns out, contain hair-like structures that form a multicontact interface, meaning geckos grip with thousands of tiny adhesive structures rather than what appears to be a single uniform foot.

Gaps remain, however, in researchers’ understanding of how gecko feet interact with surfaces in their natural environment, especially in dry versus wet conditions. Scientists know that gecko toe pads are superhydrophobic, or water repelling, yet geckos lose their ability to cling to glass when it becomes wet. Why don’t they just repel the water and cling to the glass surface below? Similarly, scientists wonder how geckos deal with wet leaves in the forest during rain storms.

A new paper published in Proceedings of the National Academy of Sciences investigates these mysteries. The authors decided to test gecko grip on a range of wet and dry materials that both attract and repel water. To perform their experiments, they outfitted six tokay geckos with gecko-sized harnesses. They placed the geckos onto four different types of materials, such as glass, plastic and a substance designed to mimic waxy tropical leaves. After giving the lizards some time to adjust to their new surroundings, the researchers applied a uniform tugging pressure onto the geckos’ harnesses, pulling in the opposite direction of where the animals were walking. Eventually, the geckos could cling no longer and lost their grip. This allowed the team to measure the adhesive force required to displace the animals. They repeated the same experiments under very wet conditions, too.

The authors found that materials that are more “wettable”—an indication of the degree to which a surface attracts water molecules—the less force it took to disrupt the clinging geckos’ grips. Glass had the highest wettability of the surfaces the researchers tested, and geckos easily slipped from wet glass compared to dry glass. When that material gets wet, water forms a thin, attractive film that prevents the gecko’s tiny toe hairs from coming into contact with the surface.

The low wettability properties of waxy leaves, on the other hand, allow geckos to establish a sturdy grip, even in rain storms, because leaves actively repel water. Geckos performed equally well in wet and dry conditions on the leaf-mimicking surface, the researchers found. 

How the geckos interact with surfaces depends upon a thermodynamic theory of adhesion, the authors conclude. These features are dictated by Van der Waals force, or the sum of attractive and repulsive interactions between gecko toes and the characteristics of the surfaces they come into contact with. So long as those attractive forces jibe, geckos are in luck for getting a grip on whatever surface they come into contact with, regardless of whether it’s wet or dry.

Using our whole-animal adhesion results, we found that wet surfaces that are even weakly [water repulsive] allow the gecko adhesive system to remain functional for clinging and likely locomotion as well.

Our findings suggest a level of versatility in the gecko adhesive system that previously was not accounted for and calls into question interesting evolutionary, ecological, and behavioral predictions.

In addition to shedding light on how gecko adaptations help the lizards cope with their natural environment, the authors think their findings may contribute to designing new synthetic gecko robots that may overcome real-life geckos’ wet glass Achilles’ heel, useful perhaps for cleaning skyscraper windows, spying on suspected terrorists, or simply changing a hard-to-reach light bulb.

Tadpole shrimp eggs can remain dormant for years, then burst into life when elusive desert rains arrive. Photo by Flickr user theloushe

As Easter draws near, we begin to notice signs of nature’s very own annual resurrection event. Warming weather begins “breeding lilacs out of the dead land,” as T.S. Elliot noted, and “stirring dull roots with spring rain.” Where a black and white wintery landscape just stood, now technicolor crocus buds peak through the earth and green shoots brighten up the azalea bushes.

Aside from this grand show of rebirth, however, nature offers several cases of even more overtly stunning resurrections. From frozen animals jumping back into action during spring thaws to life blooming from seemingly desolate desert sands, these creatures put a new spin on nature’s capacity for revival.

Resurrection fern

A resurrection fern, before and after watering. Photo by Flickr user Gardening in a Minute

As its name suggests, during a drought the resurrection fern shrivels up and appears dead, but with a little water the plant will burst back into vibrant life. It can morph from a crackled, desiccated brown into a lush, vibrant green in just 24 hours.

The fern doesn’t actually die, but it can lose up to 97 percent of its water content during an extreme dry spell. In comparison, other plants will usually crumble into dust if they lose more than 10 percent of their water content. Resurrection ferns achieve this feat by synthesizing proteins called dehydrins, which allow their cell walls to fold and reverse back to juicy fullness later.

Resurrection ferns are found as far north as New York and as far west as Texas. The ferns needs another plant to cling to in order to grow, and in the south it’s often found dramatically blanketing oak trees. A fallen oak branch covered in resurrection ferns are common features in southern gardens, though the ferns have also turned up in more uncanny locales: in 1997, astronauts took resurrection fern specimens onto the Space Shuttle Discovery to study how the plant resurrects in zero gravity. As investigators write (PDF), the fern “proved to be a hardy space traveler and exhibited regeneration patterns unaltered by its orbital adventure.” This earned it the title of “first fern in space.” 

Brine shrimp, clam shrimp and tadpole shrimp 

In the deserts of the western U.S., from seemingly life-barren rocks and sands, life blooms by just adding a little rain water. So-called ephemeral pools or “potholes” form tiny ecosystems ranging from just a few millimeters across to several meters deep. The ponds can reach up to 140 degrees Fahrenheit in the summer sun or drop below freezing during winter nights. They can evaporate nearly as quickly as they appeared, or linger on for days or weeks. As such, the animals that live there all have special adaptations for allowing them to thrive in these extreme conditions.

Ephemeral desert ponds in New Mexico. Photo: J. N. Stuart

Some of the potholes’ most captivating critters include brine shrimp (of sea monkey fame!), clam shrimp and tadpole shrimp. These crustaceans practice a peculiar form of drought tolerance: In a process known as cryptobiosis, they can lose up to 92 percent of their body water, then pop back into fully-functional action within an hour of a new rain’s arrival. To do this, the tiny animals keep their neural command center hydrated but use sugar molecules instead of water to keep the rest of their cells intact throughout the drought. Like resurrection ferns, brine shrimp, too, have been taken into space–they were successfully hatched even after being carried outside of the spacecraft. 

Most of these animals only live for about ten days, allowing them to complete their entire life cycle (hopefully) before their pool dries up. Their dried eggs are triggered to hatch not only when they’re hydrated again but also when oxygen content, temperature, salinity and other factors are just right. Some researchers, such as this zoologist quoted in a 1955 newspaper article, think that the eggs can remain dormant for several centuries and still hatch when conditions are right.

Wood frogs 

Some amphibians undergo their own sort of extreme hibernation in order to survive freezing winter temperatures. This suspended animation-like state allows them to slow down or stop their life processes–including breathing and heartbeat–just to the brink of death, but not quite. Wood frogs, for example, may encounter freezing conditions on the forest floor in winter. Their bodies may contain 50 to 60 percent ice, their breathing completely stops and their heartbeat is undetectable. They may stay like this for days, or even weeks. 

They achieve this through a specially evolved biological trick. When the frogs encounter the first signs of freezing, their bodies pull moisture away from its central organs, padding them in a layer of water which then turns into ice. Before it freezes, the frog also floods its circulatory system with sugar molecules, which act as an antifreeze. When conditions warm up again, they can make a complete recovery within a day, which researchers call “spontaneous resumption of function.” Here, Robert Krulwich explains the process: 

As seen through these examples, some creatures really do come back from the brink of death to thrive!

A model of a giant squid versus sperm whale. Photo taken at the American Museum of Natural History by Mike Goren from New York

For centuries, monsters of the deep sea captivated the imagination of the public and terrified explorers–none more so than the many-tentacled kraken. In 13th century Icelandic sagas, the Vikings wrote of a terrifying monster that “swallows both men and ships and whales and everything that it can reach.” Eighteenth century accounts from Europe describe arms emerging from the ocean that could pull down the mightiest ships, attached to bodies the size of floating islands.

Today, we’re fairly confident that a tentacled beast will not emerge from the depths to swallow up a cruise ship, but the enduring allure of such creatures lingers. None of the ocean’s massive animals, perhaps, are as intriguing as the giant squid.

Now, scientists have come one step closer to unraveling the mysteries behind this rare animal. As it turns out, contrary to some squid enthusiasts’ former hypothesis, all giant squid belong to a single species. What’s more, those animals are extremely similar genetically.

To arrive at these findings, researchers from the University of Copenhagen’s Natural History Museum of Denmark along with collaborators from 7 other countries genetically analyzed bits and pieces of 43 of the animals–which can grow more than 40 feet long and weigh nearly 2,000 pounds–recovered from all over the world.

Photo by Winkelmann et. al.

Their results indicated that, unlike most marine animals, giant squid harbor almost no genetic diversity. Remarkably, individuals as far apart as Florida and Japan, from a statistical standpoint, shared almost the same DNA. The giant squid’s genetic diversity turned out to be 44 times lower than the Humboldt squid, another large species, and seven times lower than the diversity of a population of oval squids living in a restricted area and thus prone to inbreeding. In fact, the giant squid’s diversity was lower than all other measured oceanic species, save the basking shark, which scientists believe recently underwent a severe population bottleneck in which most animals died and only a few individuals survived and repopulated the species.

The researchers can only speculate about this finding’s underlying reasons–the giant squid’s genetic data alone cannot provide a plausible explanation. Perhaps something about the giant squid makes it advantageous to cull mutations from its genome? Alternatively, the animals may have undergone a recent bottleneck, similar to what happened to the basking sharks, meaning that all giant squid following that event are closely related. Or perhaps a few foundered squid somehow wandered in new stretches of ocean, so when they populated these new habitats their offspring shared the same squid family tree. The short answer, however, is that the researchers simply do not know.

“We cannot offer a satisfactory explanation for the low diversity, and this requires future studies to resolve,” they write in a paper published this week in Proceedings of the Royal Society B.

This has been a big year for giant squid. In January, a Japanese team released the first footage of a giant squid interacting in its natural environment. Yet much still remains to be learned about these enigmatic creatures. For example, researchers still have no idea how large of a range the adult squid patrol, how long they live, how quickly they grow and whether problems such as climate change affect their populations.

For the imagination’s sake, however, perhaps it’s best if some mysteries endure.

“Despite our findings, I have no doubt that these myths and legends will continue to get today’s children to open their eyes up–so they will be just as big as the real giant squid is equipped with to navigate the depths,” said lead researcher Tom Gilbert in a statement. 

Fluorescent proteins all aglow in these corals. Photo by Michael Lesser and Charles Mazel, NOAA Ocean Explorer

Anyone who has gone scuba diving or snorkeling in a coral reef will likely never forget the dazzling colors and other-worldly shapes of these underwater communities. Home to some of the world’s most diverse wildlife hotspots, reefs are worth an annual $400 billion in tourist dollars and in the ecosystem services they provide, such as buffering shores from storms and providing habitat for fish that people eat.

Yet it’s a well known fact that coral reefs around the world are in decline thanks to pollution and rapidly warming oceans. However, determining just how reefs are faring–and designing steps to protect them–requires a way to accurately measure their health. Researchers tend to rely upon invasive, damaging techniques to figure out how corals are coping, or else they perform crude spot checks to determine reef health based on coral color alone.  But now, scientists have announced a new method of determining coral health that relies upon measuring the intensity of corals’ fluorescent glow.

Yes, glow. Corals naturally produce fluorescent proteins which glow an eery green when seen under a blue light–nearly all corals exhibit this physiological phenomenon.

“This is the first study to follow the dynamics of coral fluorescence and fluorescent protein levels during temperature stress, and shows that coral fluorescence could be utilized as a early indicator of coral stress,” said Melissa Roth, a marine biologist at the University of California, Berkeley (formerly of the Scripps Institution of Oceanography at the University of California, San Diego), in an email. “Because coral fluorescence can be measured non-invasively in the field, it could be an important tool for management of reefs,” she said. Roth and her colleague Dimitri Deheyn described their findings this week in Scientific Reports.

The degree to which a coral glows depends largely on another group of organisms, dinoflagellate algae. Corals are actually a symbiotic assembly of itself and these microscopic dinoflagellate algae–the dinoflagellates help corals attain nutrition, which in turn fuels the growth of coral reefs. The tiny organisms are also responsible for giving corals their typical brownish hue.

But dinoflagellates can abandon ship due to stressors such as increased temperature, a phenomenon known as coral bleaching. Left on their own without the aid of their dinoflagellate covering, the corals’ naturally white skin becomes glaringly visible. The coral can live for a little while after a dinoflagellate exodus, but not for long. If the algae do not return, the coral will die.

Knowing this, Roth and Deheyn decided to investigate how coral fluorescence might reflect the current state of a coral and its dinoflagellates’ relationship. They chose to use Acropora yongei, a common branching coral, in their experiments since it’s often one of the first corals shows signs of stress and bleaching in a reef. They subjected individual corals to one of two different experimental setups in their lab. In some containers, they pummeled corals with cold water, and in others they doused corals in hot water. Another group of corals served as a control. Then they let the corals pickle in their temperature-regulated waters for almost three weeks. 

The researchers found a distinct correlation between the degree of bleaching and the concentration of a coral’s fluorescent proteins, which in turn determined the strength of it’s glow. In the first 4 to 5 days, the fluorescent protein concentration and glow of both cold and heat-treated corals dropped. But by the end of the 20-day experiment, cold-stressed corals had acclimated and recovered to their normal level of fluorescence. Heat-stressed corals, on the other hand, bleached and began to glow even more strongly, probably because their dinoflagellate communities no longer blocked the coral’s underlying fluorescence. Like a supernova before a star’s final collapse, the corals send out a steady stream of intense glow just before their inevitable demise.

Corals pictures under white light (left panels) and blue light (right panels) show how corals subjected to heat stress eventually bleached and increased their fluorescent glow by the end of the experiment. Photo by Melissa Roth, Scientific Reports

After death, the glow stops. In a reef system, the bone white coral would gradually get masked by a film of green algae that coats the ruins of the now deceased organism.

Once corals start to bleach, conservationists or wildlife managers have few options for helping reefs as they begin to decline and often eventually die. But if they catch the problem ahead of time, they could try to help the coral with strategies such as shading with artificial structures or sediments, adding antioxidants to the water or introducing heartier dinoflagellates, though scientific studies validating these potential rescue methods are largely lacking. 

This new finding, Roth hopes, can be used to preempt reef collapse, serving as a sort of canary in the coal mine for corals in distress. “Managers could focus on the most sensitive corals on a reef, like branching corals, and look for rapid drops in fluorescence as an early sign of stress,” Roth said. This would give them about a week-long window to take action before full-blown bleaching began. “Bleaching would be like a heart attack,” she explained. “You would rather detect signs of high blood pressure or clogging of the arteries to address and avoid a heart attack.”

Managers who want to visualize their reef’s health can observe the glow by using a blue flashlight and a yellow filter over their snorkel mask, or they can film the phenomenon with a camera equipped with these same features. If managers notice the initial drop in coral glow that indicates an impending problem, for example, immediate action could perhaps be taken to try and rescue the reef.

“So the idea is that we can use coral fluorescence as a early indicator of coral health prior to bleaching, which could actually give time for managers to do something if they wanted to take actions to protect the reef. Obviously that may be difficult on a large scale,” she explained, adding that “as reefs become degraded the few that we have left might be protected more aggressively.”

Further research on how these findings might apply to other species of coral is needed, the authors write. They also hope that future studies will combine biology with engineering to help design a digital imaging system that better captures and quantifies the extent to which corals change their glow.

Dead locusts litter Israel’s Negev desert after being sprayed with pesticide on Wednesday. Photo: Rachel Nuwer

Locusts have plagued farmers for millennia. According to the Book of Exodus, around 1400 B.C. the Egyptians experienced an exceptionally unfortunate encounter with these ravenous pests when they struck as the eighth Biblical plague. As Exodus describes, “They covered the face of the whole land, so that the land was darkened, and they ate all the plants in the land and all the fruit of the trees that the hail had left. Not a green thing remained, neither tree nor plant of the field, through all the land of Egypt.”

Locusts attacks still occur today, as farmers in Sudan and Egypt well know. Now, farmers in Israel can also join this unfortunate group. Earlier today, a swarm of locusts arrived in Israel from Egypt, just in time for the Jewish Passover holiday which commemorates Jews’ escape from Egyptian slavery following the ten Biblical plagues. “The correlation with the Bible is interesting in terms of timing, since the eighth plague happened sometime before the Exodus,” said Hendrik Bruins, a researcher in the Department of Man in the Desert at Ben-Gurion University of the Negev in Israel. “Now we need to wait for the plague of darkness,” he joked.

With the help of the Lord, Moses delivers a plague of locusts upon the Egyptians, seen in the photo of a Bible page above. Photo via New York Public Library, Renaissance and medieval manuscripts collection

While the timing is uncanny, researchers point out that–at least in this case–locust plagues are a normal ecological phenomenon rather than a form of divine punishment. “Hate to break it to you, but I don’t think there’s any religious significance at all to insects in the desert, even a lot of them, and even if it seems reminiscent of a certain Biblically described incident,” said Jeremy Benstein, deputy director of the Heschel Center for Sustainability in Tel Aviv.

In this region of the world, locusts swarm every 10 to 15 years. No one knows why they stick to that particular cycle, and predicting the phenomena remains challenging for researchers. In this case, an unusually rainy winter led to excessive vegetation, supporting a boom in locust populations along the Egyptian-Sudanese border. As in past swarms, once the insect population devours all of the local vegetation, the hungry herbivores take flight in search of new feeding grounds. Locusts–which is just a term for the 10 to 15 species of grasshoppers that swarm–can travel over 90 miles in a single day, carried by the wind. In the plagues of 1987 and 1988 (PDF)–a notoriously bad period for locusts–some of the befuddled insects even managed to wash up on Caribbean shores after an epic flight from West Africa.

When grasshoppers switch from a sedentary, solo lifestyle to a swarming lifestyle, they undergo a series of physical, behavioral and neurological changes. According to Amir Ayali, chair of the Department of Zoology at Tel Aviv University, this shift is one of the most extreme cases of behavioral plasticity found in nature. Before swarming, locusts morph from their normal tan or green coloring to a bright black, yellow or red exoskeleton. Females begin laying eggs in unison  which then hatch in synch and fuel the swarm. In this way, a collection of 1 million insects can increase by orders of magnitude to 1 billion in a matter of months.

From there, they take flight, though the exact trigger remains unknown. Labs in Israel and beyond are working on understanding the mathematics of locust swarming and the neurological shifts behind the behaviors that make swarming possible. ”If we could identify some key factors that are responsible for this change, we could maybe find an antidote or something that could prevent the factors that transform innocent grasshoppers from Mr. Hyde to Dr. Jekyll,” Ayali said. “We’re revealing the secrets one by one, but there’s still so much more to find out.”

A swarm of locusts will consume any green vegetation in its path–even toxic plants–and can decimate a farmer’s field almost as soon as it descends. In one day, the mass of insects can munch its way through the equivalent amount of food as 15 million people consume in the same time period, with billions of insects covering an area up to the size of Cairo, Africa’s largest city. As such, at their worst locust swarms can impact some 20 percent of the planet’s human population through both direct and indirect damages they cause. In North Africa, the last so-called mega-swarm invaded in 2004, while this current swarm consists of a measly 30 to 120 million insects. 

Estimating the costs exacted by locusts swarms remains a challenge. While locust swarms reportedly cause more monetary damage than any other pest, it’s hard to put an exact figure on the problem. Totaling the true crost depends on the size of the swarm and where the winds carry it. To be as accurate as possible, costs of pesticides, food provided to local populations in lieu of wrecked crops, monitoring costs and other indirect effects must be taken into account. No one has yet estimated the cost of this current swarm, though the United Nation’s Food and Agriculture Organization (FAO) allots $10 million per year solely to maintain and expand current monitoring operations.

Locusts covering a bush during the 2004 swarm near the Red Sea cost in Israel. Photo: Amir Ayali

This morning, the Israeli Ministry of Agriculture sprayed pesticides on an area of around 1,000 hectares near the Egyptian border. To quell a plague of locusts, pest managers have to hit the insects while they’re still settled on the ground for the night and before they take flight at dawn. So far, pesticide spraying is the only option for defeating the bugs, but this exacts environmental tolls. Other invertebrates, some of them beneficial, will also shrivel under the pesticide’s deadly effects, and there’s a chance that birds and other insectivores may eat the poisoned insect corpses and become ill themselves. Researchers are working on ways to develop fungus or viruses that specifically attack locusts, but many of those efforts are still in initial investigative stages. However, the company Green Muscle developed a commercially available fungus that affects only locusts.

Even better, however, would be a way to stop a swarm from taking flight from the very beginning. But this requires constant monitoring of locust-prone areas in remote corners of the desert, which is not always possible. And since the insects typically originate from Egypt or Sudan, politics sometimes get in the way of quashing the swarm before it takes flight. “We really want to find them before they swarm, as wingless nymphs on the ground,” Ayali said. “Once you miss that window, your chances of combating them are poor and you’re obliged to spray around like crazy and hope you catch them on the ground.”

In this case, Egypt and Israel reportedly did not manage to coordinate locust-fighting efforts to the best of their abilities. “If you ask me, this is a trans-boundary story,” said Alon Tal, a professor of public policy at Ben-Gurion University. “This is not a significant enemy–with an arial approach you can nip locusts in the bud–but the Egyptian government didn’t take advantage of the fact that they have quite a sophisticated air force and scientific community just to the north.”

Ayali agrees that the situation could have been handled better. He also sees locusts as a chance to foster regional collaboration. Birders and ornithologists from Israel, Jordan and Palestine often cooperate in monitoring migratory avian species, for example, so theoretically locusts could likewise foster efforts. “Maybe scientists should work to bridge the gaps in the region,” Ayali said. “We could take the chance of this little locust plague and together make sure we’re better prepared for the next.”

For now, the Israelis have smote the swarm, but Keith Cressman, a senior locust forecasting office at the FAO’s office in Rome warns that there is still a moderate risk that a few more small populations of young adults may be hiding out in the desert. This means new swarms could potentially form later this week in northeast Egypt and Israel’s Negev region. His organization warned Israel, Egypt and Jordan this morning of the threat, and Jordan mobilized its own locust team, just in case.

For those who do come across the insects (but only the non-pesticide covered ones!), Israeli chefs suggest trying them out for taste. Locusts, it turns out, are the only insects that are kosher to eat. According to the news organization Haaretz, they taste like “tiny chicken wings,” though they make an equally mean stew. “You could actually run out very early before they started spraying and collect your breakfast,” Ayali said. “I’m told they’re very tasty fried in a skillet, but I’ve never tried them myself.”

A swarm of locusts descends upon Israel. Photo by Amir Ayali

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A bull male forest elephant in Gabon. A new study published in the PLOS ONE shows that African forest elephants are being poached into extinction. Photo by Elizabeth M. Rogers

When you think of an elephant, you probably picture a big-tusked bull stampeding through vast African grasslands. But there are more to elephants than this run-of-the-mill savannah variety. The African forest elephant—recently declared a distinct species from its plains-dwelling cousin–lives exclusively in the forests of Central Africa. Males rarely exceed 8 feet in height, compared to about 13 feet for savannah elephants–all the better for navigating through the jungle trees. They eat mostly fruit, and researchers think they play a key role in spreading seeds and shaping the forest’s environment and structure through their comings and goings.

But like many other animals living in Africa and Asia, this unique species is in decline as a result of rampant poaching for its ivory and loss of its forest habitat to human development. A new study led by the Wildlife Conservation Society and published in PLoS One puts those threats into perspective, and the news is not good. The situation for forest elephants is much worse than we thought, the paper announces, and unless we act quickly, the survival of these miniature elephants is in jeopardy.

Until now, conservationists had little idea of where exactly forest elephants live and how many of them there are. A team of 62 researchers from African, Europe and North America–the authors of the study–pooled their expertise and research efforts to figure out this basic information. Without these data, organizations such as the International Union for the Conservation of Nature (IUCN) cannot properly assess whether a species qualifies as endangered or not.

From 2002 to 2011, the team members conducted more than 80 forest elephant surveys in the jungles of Central Africa, focusing on five countries–Cameroon, Congo, the Central African Republic, the Democratic Republic of Congo, and Gabon. The scientists traveled on foot, covering around 13,000 kilometers of jungle. To determine elephant presence and density, the researchers set up transects to sample elephant dung, collecting more than 11,000 samples in total. Based on the amount of dung found, they extrapolated estimates of elephant population within a given area.

Their survey results were startling. They found “a widespread and catastrophic decline” of forest elephants, they write, corresponding to about a 62 percent decrease in forest elephant population size between the nine years of their survey. The elephants lost around 30 percent of their range during that time period, and they occupy just 25 percent of their potential forest habitat. The authors say that the population of forest elephants is now less than 10 percent of what it could be, given the extent of its habitat.

The paper conservatively estimates that around half a million forest elephants roamed Central Africa in the 1930s, but now 80 percent have been lost, leaving the population at an estimated 100,000 animals at most. In the Democratic Republic of Congo’s protected Okapi Faunal Reserve, for example, 5,100 elephants—75 percent of the park’s population—were killed over the past 15 years. In Gabon’s Minkébé National Park, officials announced earlier this year that roughly 11,000 forest elephants have been poached since 2004. The paper puts these reported losses into broad perspective.

“This is the first range-wide, data-driven study confirming that Central Africa is hemorrhaging elephants on an unprecedented scale,” said Samantha Strindberg, a researcher at the Wildlife Conservation Society and one of the study’s lead authors, in a statement. “The analysis confirms what conservationists have feared: the rapid trend towards extinction–potentially within the next decade–of the forest elephant, according to the authors.”

In the last few years, poaching for ivory and other wildlife products has escalated. Analyses performed by the Elephant Trade Information System and the Monitoring the Illegal Killing of Elephants program–both maintained by the Convention on International Trade in Endangered Species–confirmed that this escalation in illegal trade is largely due to a strong demand for and increase in value of ivory in China, where ivory carvings are prized and ivory powder is sold as a folk cure for cancer. The black market for ivory is estimated to have netted more than $264 million over the past decade.

A cache of illegal ivory goods confiscated New York City last year were worth an estimated $2 million. Photo via Manhattan District Attorney’s Office.

While this problem is typically associated with slain savannah elephants, the growing crisis increasingly applied to forest elephants as well. In addition to the increase in price and demand for ivory, the authors add that: 

The persistent lack of effective governance in Central Africa and a proliferation of unprotected roads that provide access to hunters combine to facilitate illegal ivory poaching, transport and trade. Forest elephant population and range will continue to decline unless conditions change dramatically.

Habitat loss, often to oil palm plantations for biofuel production, further exacerbates the problem, they write.

Given this dire situation, the authors call for the IUCN to add the African forest elephant onto their species Red List as Critically Endangered (the IUCN currently lists forest elephants as a subspecies of savannah elephants). This upgrade would draw international attention to the problem, the authors hope, which may help boost efforts and support to curb poaching. But reducing demand for ivory, the authors remind, remains the best way to ensure the survival of forest elephants and the countless other species impacted by the illegal wildlife trade.

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A male human head louse. Photo by Flickr user Gilles San Martin

Parasites have been around for more than 270 million years. Around 25 million years ago, lice joined the blood-sucking party and invaded the hair of ancient primates. When the first members of Homo arrived on the scene around 2.5 million years ago, lice took advantage of the new great ape on the block for better satisfying its digestive needs. As a new genetic analysis published today in PLoS One shows, mining these parasites’ genomes can lend clues for understanding the migration patterns of these early humans.

The human louse, Pediculus humanus, is a single species yet members fall into two distinct camps: head and clothing lice–the invention of clothing likely put this divide into motion. Hundreds of millions of head lice infestations occur each year around the world, most of them plaguing school-aged children. Each year in the United States alone, lice invade the braids and ponytails of an esimtated 6 to 12 million kids between the ages of 3 to 11. Clothing lice, on the other hand, usually infect the homeless or people confined to refugee camps. Clothing lice–also referred to as body lice–are less prevalent but potentially more serious because they can serve as vectors for diseases such as typhus, trench fever and relapsing fever.

Researchers have studied the genetic diversity of head and clothing lice in the past, but scientists from the Florida Museum of Natural History at the University of Florida decided to tap even deeper into the parasites’ genome, identifing new sequences of DNA that could be used as targets for tracking lice evolution through time and space. From these efforts, they found 15 new molecular markers, called microsatellite loci, which could help uncover the genetic structure and breeding history behind different lice populations–and potentially their corresponding humans of choice.

Using those genetic signals, they analyzed the genotypes of 93 human lice taken for 11 different sites around the globe, including North America, Cambodia, Norway, Honduras, the UK and Nepal, among others. They collected lice from homeless shelters, orphanages and lice eradication facilities.

Inbreeding, it turned out, is common in human lice around the world. Lice in New York City shared the most genetic similarities, pointing to the highest levels on inbreeding from the study samples. Clothing lice tended to have more diversity than head lice, perhaps due to an inadvertent bottlenecking of the head lice population due to high levels of insecticides those parasites are regularly exposed to. As a result of repeated run-ins with anti-lice shampoos and sprays, only the heartiest pests would survive, restraining the overall diversity of the population. Insecticide resistance is a common problem in head lice, but less of an issue with clothing lice. The authors identified one possible gene that may be responsible for much of the head louse’s drug resistance, though further studies will be needed to confirm that hunch. 

The researchers also analyzed lice diversity to see how it relates to human migration. They found four distinct genetic clusters of lice: in clothing lice from Canada, in head lice from North America and Europe, in head lice from Honduras and in all Asian lice.

Here’s the authors present a map of lice genetic diversity. The colored circles indicate sampling sites, with the different colors referring to the major genetic clusters the researchers identified. The grey flowing arrows indicate proposed migrations of modern humans throughout history, and the colored arrows represent the hypothetical co-migration of humans and lice.

Photo from Ascunce et al., PLoS One

How this geographic structure reflects human migration, they write, will require more sampling. For now, they can only speculate about the implications:

Although preliminary, our study suggests that the Central America-Asian cluster is mirroring the (human host) colonization of the New World if Central American lice were of Native American origin and Asia was the source population for the first people of the Americas as has been suggested. The USA head louse population might be of European decent, explaining its clustering with lice from Europe. Within the New World, the major difference between USA and Honduras may reflect the history of the two major human settlements of the New World: the first peopling of America and the European colonization after Columbus.

Eventually, genetic markers in lice could help us understand interactions between archaic hominids and our modern human ancestors, perhaps answering questions such as whether or not Homo sapiens met with ancient relatives in Asia or Africa besides Homo neanderthalensis. Several kinds of louse haplotypes, or groups of DNA sequences that are transmitted together, exist. The first type originated in Africa, where its genetic signature is strongest. A second type turns up in the New World, Europe and Australia, but not in Africa, suggesting that it may have evolved first in a different Homo species whose base was in Eurasia rather than Africa. If true, then genetic analysis may give us a time period for when humans and other Homo groups for came into contact. And if they interacted close enough to exchange lice, perhaps they even mated, the researchers speculate.

So not only can the genetic structure of parasite populations help us predict how infections spread and where humans migrated, it may give insight into the sex-lives of our most ancient ancestors.

Footage from Brazil’s “spider rain.” Photo: TV45000

The Northeast may be prone to blizzards this time of year, but in Brazil it’s raining spiders. In a video that’s covered the Internet like an immense web, a local photographer captures images of thousands of spiders shimmying up and down silk threads attached to telephone pole wires. The footage gives the distinct impression of a shower–or perhaps light snow–of spiders sprinkling down on the shocked residents below.

Erick Reis, a 20-year-old web designer in Santo Antonio da Platina, a town about 250 miles west of Sao Paulo, captured the striking video that has since accumulated more than 2 million YouTube views over the course of the week.  “I was shooting an engagement party for some friends of mine and I saw the spiders when I was leaving, now in the late afternoon,” he explained to TV450000, which posted the video. “I’ve never seen anything like it before.”

According to biologist Marta Fischer of the Pontifical Catholic University of Parana, however, the phenomenon is not so strange. ”This type of spider is known to be quite social,” she said. “They are usually in trees during the day and in the late afternoon and early evening construct sort of giant sheets of webs, in order to trap insects.”

Scientists have described around 40,000 species of spiders around the world, but only a handful of them are social. These 23 species are scattered around the world and sometimes swarm, like ants or bees. Females often outnumber males 10 to 1 in colonies that can exceed 50,000 individuals.

Around Sao Paulo and its neighboring cities, she said, it’s not an unusual site to see a sky speckled by spiders. The species, Anelosimus eximius, can be found from Panama to Argentina and lives in colonies sometimes comprised of thousands of individuals. Each spider is around the size of a pencil eraser. As Examiner reports, the species’ webs can stretch from the ground up to tree canopies or human constructions 65 feet high.

If strong winds come along, the web may detach from its anchors, carrying the spiders and their ruined home to new sites where they appear to “rain down.” Catching rides on the wind–en mass–was likely what happened in Santo Antonio da Platina. While the humans gawked below, the flustered spiders were simply trying to pull themselves together after an unexpected journey from some forest or park.

Before North American readers breathe a sigh of relief that this isn’t happening a bit closer to home, however, it’s worth noting that similar colonies live in Texas. In Lake Tawakoni State Park, just east of Dallas, Guatemalan long-jawed spiders construct enormous webs covering up to 600 foot stretches. The spiders build the huge webs in less than two weeks. Researchers think the spiders achieve such sudden engineering feats thanks to their “remarkable reproductive capabilities and ability to disperse by ballooning,” according to A Field Guide of Scorpions and Spiders of Texas.

So far, Dallas residents haven’t reported massive sheets of webs and their arachnid residents “ballooning” into backyards. But, as witnessed by residents of Santo Antonio da Platina,  stranger things have happened. 

Photo by Philippe Verbelen

Indonesia’s numerous islands (18,307 to be exact) house a wealth of avian biodiversity, yet scientists speculate that many of the country’s bird species have yet to be discovered or categorized. But ornithologists are celebrating today as a new species of owl joins the list, taking filling in one more spot in the catalog of the archipelago’s animals.

In 2003, George Sangster, a Dutch ornithologist from Stockholm University, and his wife were exploring the forested foothills of Lombak, an island just east of Bali. While traipsing through the forest at night, Sangster picked up on an owl call he did not recognize. Coincidentally, just a few days later Ben King, an ornithologist from the American Museum of Natural History, heard those same calls from the jungle and also suspected they came from an unknown species.

“It was quite a coincidence that two of us identified this new bird species on different parts of the same island, within a few days of being on the island, especially considering that no-one had noticed anything special about these owls in the previous 100 years,” Sangster said in a statement.

Locals on Lombak, it turned out, were familiar with the species. Known as burung pok–roughly translated as “pook,” a mimic of the owl’s hoots–the birds turned out to be a common feature of the nocturnal landscape. But locals on neighboring islands, however, said they had never heard of the bird and did not recognize its unusual call.

Here, you can hear the little Indonesian owl hooting into the night, which the researchers describe as “a single whistle without overtones:

Although birders and scientists alike love owls, surprisingly not much is known about those species’ biology, including how they relate to one another on an evolutionary scale. Lately, however, researchers have been working double time to get a grip on owls. In 1975, for example, scientists knew of 146 species, and that number leapt to 250 as of 2008. One driver behind this jump in species numbers was the realization that owl calls could lend clues (PDF) to classifying different types of owls. Owls hoot to attract mates and recognize one another as the same, so animals evolved calls unique to their species. In some cases, owls previously classified as the same species were split in two primarily on the basis of their calls.

Sangster, King and two other researchers from Sweden and Australia got together and were able to photograph the owls by playing back recordings of the call to attract several of the hooting culprits. Digging through old records, the researchers found that the owls matched specimens collected back in 1896 by Alfred Everett, a British administrator who was based in Borneo and spent his spare time collecting natural history curios. That same year, Ernest Hartlet, a naturalist who reported on Everett’s field work, accurately noted that “the cry is a clear but not very loud ‘pwok,’ like that of [O.] lempiji, but somewhat different in tone.”

Though Hartlet and Everett came close to identifying the new species, they fell just short of making the leap. Since then, no one had collected or observed this type of owl, according to records from the American Museum of Natural History and the Natural History Museum at Tring, in the U.K. 

All of this evidence, the team concluded in a PLoS ONE paper, pointed to the discovery of a new species of owl.

Because the new owl shows dramatically less individual variation to its brown and cream-speckled feather patterns than similar species found on neighboring islands, the scientists hypothesize that ancestors of the Lombok owls may have been isolated and trapped on their island many years before by a catastrophic volcanic eruption. Starting with just a handful of individuals, the animals then could have slowly rebuilt their populations, eventually evolving into a unique lineage.

The species, they report, is the first bird known to be unique to Lombok. The authors named the new bird Otus jolandae, after Sangster’s wife, Jolanda.