A good eye will spot the black-marble jawfish next to the mimic octopus's arm (Credit: Godehard Kopp)

The mimic octopus (Thaumoctopus mimicus) has the uncanny ability to make itself look like more dangerous creatures, such as lionfish, sea snakes and soles. The octopus does this with its distinctive color pattern and ability to adjust its shape and behavior (see this earlier blog post on the octopus for a video in which it mimics a flatfish). But now the mimic has a mimicker of its own, scientists report in the journal Coral Reefs.

Godehard Kopp  of the University of Gottingen in Germany was filming a mimic octopus during a diving trip to Indonesia last July when he spotted a companion–a small fish that followed the octopus for several minutes, always sticking close to the octopus’s arms. Kopp has some good observational skills, because the fish’s color and banding looks incredibly similar to that of the octopus.

Kopp sent his video (see below) to two marine scientists at the California Academy of Sciences who identified the fish as a black-marble jawfish (Stalix cf. histrio). The three write:

Jawfish are poor swimmers and usually spend their entire adult lives very close to burrows in the sand, to where they quickly retreat, tail first, upon sight of any potential predator….[In Kopp's video and photos], the Black-Marble Jawfish seems to have found a safe way to move around in the open. The Mimic Octopus looks so much like its poisonous models that it is relatively safe from predation, even when swimming in the open, and by mimicking the octopus’ arms, the Jawfish seems to also gain protection.

This might at first glance appear to be a case in which the fish evolved its coloring to gain protection by associating with the octopus, but the scientists don’t think that’s likely. The jawfish can be found from Japan to Australia, but the octopus lives only in the region around Indonesia and Malaysia. They contend that this is a case of “opportunistic mimicry,” in which the fish is taking advantage of a happy coincidence.

A composite image of S106, from the Hubble Space Telescope and Japan's Subaru Telescope (Credits: NASA/ESA/the Hubble Heritage Team (STScI/AURA)/NAOJ)

About 2,000 light years away, in the direction of the constellation Cygnus (The Swan), in a rather isolated part of the Milky Way, lies a newly formed star known IRS 4. This star, about 15 times the mass of our Sun, is still so young that it hasn’t yet calmed down; it’s ejecting material at high speed, giving this image its wings. That hydrogen gas, colored blue here, is heated by the star to temperatures of 10,000 degrees Celsius, making them glow. The cloudy, red parts in the image are tiny particles of dust illuminated by the star.

This area of the universe is known as star-forming region S106 and it’s pretty small (well, by universe standards), at only two light years from the edge of one “wing” to the other. The nebula is also home to more than 600 known brown dwarfs, “failed” stars that, because of their size, less than a tenth the mass of our Sun, cannot undergo the nuclear fusion that powers glowing stars.

Check out the entire collection of Surprising Science’s Pictures of the Week and get more science news from Smithsonian on our Facebook page.

In this image from December 15, 2011, Comet Lovejoy appeared to be headed towards sure destruction in a collision with the Sun (credit: NASA/SOHO)

Amateur astronomer Terry Lovejoy of Australia discovered a comet in 2007 using nothing more than a digital camera. Comet Lovejoy was a large member of the Kreutz family of comets–fragments of a large comet that broke up hundreds of years ago but still travel in its path, grazing the surface of the Sun and sometimes colliding with it. And yesterday it looked like Comet Lovejoy would meet such a fiery end.

But that didn’t happen.

Despite scientists’ predictions that the comet would not survive its encounter with the Sun, Comet Lovejoy lives on. The Associated Press reports:

The comet came within 75,000 miles of the sun. For a small object often described as a dirty snowball, that brush with the sun should have been fatal.

Astronomers say it probably wasn’t deadly because the comet was larger than they thought.

Comet Lovejoy’s near-fatal journey was well-watched by scientists who have a fleet of satellites pointed at our Sun. You can watch the comet streak through the Sun’s atmosphere in the video below, taken by NASA’s Solar Dynamics Observatory, or see the comet’s path around the Sun in the animated gif (below the video), created with images from the NASA satellite SOHO.

Comet Lovejoy survived its close encounter with the Sun (credit: NASA/SOHO)

A map of extreme weather events in the United States, January to October 2011 (credit: NRDC)

The United States may not have seen anything like Hurricane Katrina this year, but it’s been a bad year for extreme weather events nonetheless. High heat, drought and wildfires in Texas. Flooding in the Midwest and Northeast. Deadly tornadoes. The Natural Resources Defense Council found nearly 3,000 broken weather records throughout the United States, and that count went only through the end of October. A map compiling the locations of these events is above; an interactive version that lets you visualize the events through time can be found on the NRDC website.

Scientists are reluctant to say any specific weather event is the result of climate change (weather and climate are, after all, not interchangeable). But they do largely agree that extreme weather events, such as the ones we’ve seen this year, will become more and more common because of climate change.

And those events come with a price. NRDC provided an estimate of $53 billion associated with the events in the group’s tally–if climate change contributed even a fraction to these events, we’re looking at potentially billions of dollars lost. And a country climbing out of a recession could surely use that money elsewhere.

What will humankind do about this? Well, 15,000 delegates are currently meeting in Durban, South Africa, to discuss just that, but little is expected to come out of the meeting. Christie Aschwanden at The Last Word on Nothing thinks part of the reason for current inaction is how we look at the whole situation:

The problem can seem insurmountable, and it’s possible that it is—not because there is no solution, but because we are incapable of choosing it. There’s a one-word solution to the climate (and energy) problem staring us in the face—restraint. Simply consuming less. It’s too late to talk about carbon emissions. With a population catapulting toward nine billion or more, it’s time to focus on carbon omissions.

Restraint is not the easy, no-need-to-change-a-thing solution that people keep pretending we will find. But it’s a reality-based solution that will happen whether we want it to or not. We can plan for it and make the hard choices ourselves, or we can wait for them to be forced upon us. Using less doesn’t necessarily mean lowering our quality of life, it means redefining how we measure our wellbeing.

I’m not sure “restraint” will be any easier of a message to sell to a global population, and particularly a U.S. population, than “reducing carbon emissions,” but it’s an interesting way to look at the problem. If the old ideas aren’t working, we need new ones.

So here’s the challenge: How should we go about addressing climate change? Are global agreements worth the time, energy and carbon emissions it takes to make them? Do small changes made in your own home make any difference? If you were in charge, what would you do? I’m really hoping that one of you has a good answer (tell us in the comments below), because these extreme weather events are taking a toll and humans need to do something to prevent the worst from happening.

Hawkmoths prefer columbines with long, slender spurs. (Courtesy of Scott A. Hodges/UCSB)

Adaptive radiation is a principle in evolutionary biology in which one species, in response to opportunities in its environment, quickly adapts and develops new traits and diversifies into many species. An example of adaptive radiation is found in columbine flowers (genus Aquilegia), a group of about 70 species that have nectar spurs extending from the base of the flower petals. What makes these spurs special is that each species has spurs of a different length, seemingly tailored to that species’ pollinator, whether it be a hummingbird, hawkmoth or bee.

Scientists since Charles Darwin have observed similar examples of adaptive radiation but have been unable to describe what happens on a cellular or genetic scale. “Darwin, observing orchids, recognized that the extraordinarily long nectar spur on the Angraecum must have evolved in concert with the equally long tongue of the moth that pollinated it, but the exact mechanism for this kind of adaptation has been a matter of speculation,” says Sharon Gerbode of Harvard University.

Gerbode and her colleagues at Harvard and the University of California at Santa Barbara investigated that mechanism in columbines and report their findings in the Proceedings of the Royal Society B. For decades, scientists had thought that the differences in nectar spur length were due to the number of cells in the nectar spur. But when the researchers counted the number of cells and calculated the area and degree of elongation of each cell–which required more than 13,000 measurements across several species–they found that the assumptions were wrong. Nearly all of the difference in spur length can be attributed to the length of the cells.

In each species, cell division in the nectar spur stops when the spur is about 5 millimeters long. Then the spurs begin to elongate, and how many days they spend growing determines the eventual length of the spur.

“Now that we understand the real developmental basis for the first appearance and diversification of spurs, we can make more informed guesses about what genes contributed to the process,” says study co-author Elana Kramer. Further research should give the scientists insight into the genetic basis behind the radiation of this genus.

Check out the entire collection of Surprising Science’s Pictures of the Week and get more science news from Smithsonian on our Facebook page.

An elephant seal in bull kelp, in the Southern Ocean (credit: Christopher J. Brown)

It’s gonna get messy, particularly in the oceans. That seems to be the message in a recent Science study that analyzed the pace of climate change.

A marine sea slug (credit: Hugh Brown, Scottish Association for Marine Science)

Using 50 years of observations, “we examined the velocity of climate change (the geographic shifts of temperature bands over time) and the shift in seasonal temperatures for both land and sea,” said John Pandolfi of the University of Queensland. “We found both measures were higher for the ocean at certain latitudes than on land, despite the fact that the oceans tend to warm more slowly than air over the land.”

The changes won’t be uniform, the scientists say. And some marine organisms will have to migrate hundreds of miles to new waters to find the right temperature, seasonal conditions and food. Those that don’t move fast enough could easily become extinct.

And it isn’t as simple as moving north or south toward the poles. Like most landscapes, oceans aren’t uniform. There are land masses and deep ocean trenches and strong currents that can prevent creatures from moving from one place to another. Then there’s the question of what might take the place of the organisms that currently live in the warmest parts of the oceans. “No communities of organisms from even warmer regions currently exist to replace those moving out,” Pandolfi said.

An Adelie penguin in a blizzard (credit: Christopher J. Brown)

In an accompanying Perspective essay, biologist Ralf Ohlemüller of Durham University notes that “climate affects both evolutionary processes, such as how fast species diversify, and ecological processes, such as range shifts and species interactions.” And while that complexity of interactions will make predicting the coming changes difficult, Ohlemüller reminds us that studies like this one, which are not as detailed as we might like, are important nonetheless as they help us to “broaden our understanding of how environments change in space and time and how this in turn affects patterns of disappearing, persisting, and novel climates, species, and ecosystems.” And with that knowledge, perhaps we can be better prepared for the changes ahead.

Check out the entire collection of Surprising Science’s Pictures of the Week and get more science news from Smithsonian on our Facebook page.

A false-color image of flooding in Bangkok, Thailand (Image Credit: NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team)

If you think we’ve been having a wild weather year here in the United States (with droughts, horrible tornadoes, a freakishly early northeast snowstorm, to mention a few events), be glad you’re not in Thailand. From NASA:

Since July 2011, heavy monsoon rains in southeast Asia have resulted in catastrophic flooding. In Thailand, about one third of all provinces are affected. On Oct. 23, 2011, when this image [above] from ASTER, the Advanced Spaceborne Thermal Emission and Reflection Radiometer instrument on NASA’s Terra spacecraft was acquired, flood waters were approaching the capital city of Bangkok as the Ayutthaya River overflowed its banks. In this image, vegetation is displayed in red, and flooded areas are black and dark blue. Brighter blue shows sediment-laden water, and gray areas are houses, buildings and roads.

And if it wasn’t bad enough to have your home flooded, have to search for food and clean water along with other drenched city dwellers and have the threat of illnesses like cholera hanging over your head, Bangkok’s residents also have to avoid the crocodiles let loose from flooded crocodile farms.

Meanwhile, scientists are warning that climate change will bring even weirder and worse weather events in the future. “The extremes are a really noticeable aspect of climate change,” Jerry Meehl, senior scientist at the National Center for Atmospheric Research, told the Guardian. “I think people realize that the extremes are where we are going to see a lot of the impacts of climate change.”

Check out the entire collection of Surprising Science’s Pictures of the Week and get more science news from Smithsonian on our Facebook page.

The Terkezi Oasis in Chad, as seen from Landsat 7 (Credit: USGS)

When someone at the USGS Earth Resources Observation and Science Center saw this image of the Terkezi Oasis in Chad, taken by the Landsat 7 satellite, he or she saw art and included it in the Earth as Art collection. But when I came upon it, and mentally rotated it by 90 degrees (as shown above), I saw a ghostly screamer with one arm raised in anger.

Admittedly, I had primed my brain for such a discovery, searching for Halloween-ish images in keeping with the season, but I probably would have seen a face even if I hadn’t been thinking of monsters and ghosts. We often find patterns in places where they don’t exist, whether it be a witch’s head in a nebula, initials in the echoes of the Big Bang or the Virgin Mary in a piece of toast.

There are definite advantages in being able to recognize patterns—when they are real, they can provide useful information about the world around us, information that can help us to prosper and stay alive. But we haven’t necessarily evolved to tell real patterns apart from false ones, as Michael Shermer pointed out in Scientific American a few years ago:

Unfortunately, we did not evolve a Baloney Detection Network in the brain to distinguish between true and false patterns. We have no error-detection governor to modulate the pattern-recognition engine. (Thus the need for science with its self-correcting mechanisms of replication and peer review.) But such erroneous cognition is not likely to remove us from the gene pool and would therefore not have been selected against by evolution.

Shermer points to a study in Proceedings of the Royal Society B that examined the phenomenon and demonstrated that whenever the cost of believing in a false pattern (e.g., ghosts are real) is less than the cost of not believing in a real pattern (e.g., snakes of a specific color can kill), then natural selection will favor the belief in patterns, whether real or not. “Such patternicities, then, mean that people believe weird things because of our evolved need to believe nonweird things,” Shermer writes.

So if you believe in ghosts or witches or other things that go bump in the night, I guess you can blame evolution.

An artist's conception of the star LkCa 15 and the nearby protoplanet. (Credit: Karen L. Teramura, UH IfA)

Planets form from disks of swirling material that condense into solid bodies. Once only a theory, this formation has now been caught in the act by scientists using telescopes at the W.M. Keck Observatory in Hawaii (a site that should be familiar if you’ve read the Smithsonian story on black holes). The planet’s name is LkCa 15 b and researchers say it’s a protoplanet (below, in blue), still surrounded by cool dust and gas (in red). “We…found a planet, perhaps even a future solar system at its very beginning,” says the University of Hawaii’s Adam Kraus, lead author of the study that will appear soon in the Astrophysical Journal.

The planet LkCa 15 b appears in blue surrounded by cooler dust and gas in red, near the star LkCa 15. (Credit: Kraus & Ireland, 2011)

Kraus and his co-author, Michael Ireland of Australia’s Macquarie University, made their discovery by combining two techniques to cancel out the light from bright stars. The first is adaptive optics, which uses powerful computers to rapidly manipulate the telescope’s mirrors and adjust for distortions caused by Earth’s atmosphere. The second is aperture mask interferometry, and it further improves the resolution of the telescope. “We can manipulate the light and cancel out distortions,” Kraus says. They pointed the telescope at the star LkCa 15, canceled out the star’s light and there it was, a newly forming planet.

“LkCa 15 b is the youngest planet ever found,” Kraus says. “This young gas giant is being built out of the dust and gas….For the first time, we’ve been able to directly measure the planet itself as well as the dusty matter around it.”

Phil Plait, at Bad Astronomy, has more details:

The disk’s hole is about 8 billion km across. Disks like this are seen around other stars, and it’s generally thought that the hole is caused by a planet orbiting inside that region sweeping up material. In this case, that looks to be true! If the planet is in a circular orbit, it’s about 2.5 billion kilometers from its star, a little closer to its star than Uranus is from the Sun (it’s not known if the orbit is circular or elliptical; that’ll take a few years of observations as the planet physically moves around the star and the orbit can be calculated). The planet is much hotter than you might expect, but that’s because it’s so young: material is falling onto it, heating it up. That’s why it’s glowing in the infrared.

…Nothing like this has been seen before in a planet so young! That’s scientifically quite important. Our models of how planets form are complex, and we need detailed observations to see if the models are correct or not. Since planet formation is a process, we need observations of it at different stages, including very early on. That’s crucial, since it represents the transition period between the time before planets start to form in the disk, and the time when the planets are all finished and tidied up. We’ve seen both of those before, so this observation is a first.

Check out the entire collection of Surprising Science’s Pictures of the Week and get more science news from Smithsonian on our Facebook page.

Internal parts of a wildflower, magnified 100x, by Arik Shapira of Hod HaSharon, Israel (Nikon Small World)

The Nikon Small World Photomicrography Competition is always a favorite in my office. The imagery—created with any of a number of techniques that magnify and enhance objects—ranges from the fantastical to the freaky, but it often has the added benefit of being useful in scientific research. This year Nikon, which announced the 2011 winners earlier this month, has added a Popular Vote feature, which is open until October 30 (the photo above is currently near the top of the leaderboard). And if you have an amazing photomicrograph or digital video (a new category for 2012), you can find rules and entry forms here.

But I can hardly talk about a photo contest without mentioning Smithsonian magazine’s own 9th Annual Photo Contest. You can enter images in one of five categories—Altered Images, Americana, the Natural World, People and Travel—and even if you don’t make the finals, your photo may be featured as one of our daily Editor’s Picks online. The contest is open until December 1, 2:00 p.m. EST, and finalists will be announced on March 1, 2012.

Check out the entire collection of Surprising Science’s Pictures of the Week and get more science news from Smithsonian on our Facebook page.

King of the Hill by photographer James Kasher

Fall is one of the most photogenic times of year, a good time to be on the lookout for subjects for Smithsonian Magazine’s Photo Contest. The leaves are changing, migratory birds are flying south and absurd produce is being harvested (read all about thousand-pound-plus pumpkins).

One of the finalists in the Natural World category from our 8th Annual Photo Contest is from photographer James Kasher. He explains how he got the shot, taken off of the island of Bonaire in the Netherlands Antilles:

As I was swimming above the pristine reef, I noticed an isolated anemone that had stunning purple tips. As I got closer I became mesmerized with its beauty and texture. Upon closer inspection I noticed a few anemone shrimp tucked away near the bottom of the anemone fingers. Every so often they would move and reposition themselves in different areas.

A few moments later one appeared on the very top of one of the highest fingers. It grasped the tip in what appeared to be a moment of victory: King of the Hill.

If you’ve caught your own moment of victory (or defeat) on film, enter our 9th Annual Photo Contest. The deadline is December 1.

Most orchid bees, like this Euglossa paisa, have metallic coloration (credit: S. Ramirez, 2005)

When scientists delve into studies of the co-evolution of plants and their pollinators, they have something of a chicken/egg problem—which evolved first, the plant or its pollinator? Orchids and orchid bees are a classic example of this relationship. The flowers depend on the bees to pollinate them so they can reproduce and, in return, the bees get fragrance compounds they use during courtship displays (rather like cologne to attract the lady bees). And researchers had thought that they co-evolved, each species changing a bit, back and forth, over time.

But a new study in Science has found that the relationship isn’t as equal as had been thought. The biologists reconstructed the complex evolutionary history of the plants and their pollinators, figuring out which bees pollinated which orchid species and analyzing the compounds collected by the bees. It seems that the orchids need the bees more than the bees need the flowers—the compounds produced by the orchids are only about 10 percent of the compounds collected by the bees. The bees collect far more of their “cologne” from other sources, such as tree resin, fungi and leaves.

And it was the bees that evolved first, the researchers found, at least 12 million years before the orchids. “The bees evolved much earlier and independently, which the orchids appear to have been catching up,” says the study’s lead author, Santiago Ramirez, a post-doc at the University of California at Berkeley. And as the bees evolve new preferences for these chemical compounds, the orchids follow, evolving new compounds to lure back their bee pollinators.

But this study is more than just an interesting look into the evolution of two groups of organisms. The researchers note that in the context of the current decline of bee populations worldwide, their research has disturbing implications for what that decline might mean for plants. “Many of these orchids don’t produce any other type of reward, such as nectar, that would attract other species of bee pollinators,” Ramirez notes. “If you lose one species of bee, you could lose three to four species of orchids.”

Check out the entire collection of Surprising Science’s Pictures of the Week and get more science news from Smithsonian on our Facebook page.

The moose likely got drunk eating apples fermenting on the ground. AP Photo/Per Johansson

You may have seen the story earlier this week of the drunken Swedish moose (or elk, as they call the antlered behemoth in Sweden) that got stuck in a tree. “I thought at first that someone was having a laugh. Then I went over to take a look and spotted an elk stuck in an apple tree with only one leg left on the ground,” Per Johansson, who spotted the inebriated mammal in the garden next door to his house in Särö, told The Local. The moose likely got drunk eating apples fermenting on the ground and got stuck in the tree trying to get fresh fruit. “Drunken elk are common in Sweden during the autumn season when there are plenty of apples lying around on the ground and hanging from branches in Swedish gardens,” The Local states.

Moose aren’t the only non-human animals with a taste for alcohol, though.

The pen-tailed treeshrew of Malaysia gets credit for having the world’s highest alcohol tolerance. Seven species of animals, including the treeshrew and the slow loris, feed on fermented nectar from the flower buds of the bertam palm plant. But though the treeshrew quaffs this brew all day long, it doesn’t get drunk, scientists found in a 2008 PNAS study. “They seem to have developed some type of mechanism to deal with that high level of alcohol and not get drunk,” University of Western Ontario microbiologist, and study co-author, Marc-André Lachance told LiveScience. “The amount of alcohol we’re talking about is huge—it’s several times the legal limit in most countries.”

Fruit bats also appear to tolerate the effects of fermentation on fruit better than the Swedish moose did. In a 2010 PLoS ONE study, scientists fed wild-caught fruit bats sugar water laced with alcohol and sent them through a maze. Though many of the bats would have gotten a FUI (flying under the influence) citation, they had no more trouble navigating than did bats given sugar water alone. The researchers think that being able to tolerate alcohol lets the bats have access to a food source—fruit—for a longer period than only when it’s ripe.

Rhesus macaques, however, are more like humans than treeshrews, according to a 2006 Methods study in which the monkeys were given access to an alcoholic drink in a series of experiments. “It was not unusual to see some of the monkeys stumble and fall, sway, and vomit,” study co-author Scott Chen, of the National Institutes of Health Animal Center, told Discovery News. “In a few of our heavy drinkers, they would drink until they fell asleep.” The macaques frequently drank until their blood reached the .08 level that would disqualify them from driving a car in most states. And when the researchers looked at patterns of drinking, macaques that lived alone tended to drink the most. In addition, they drank more at the end of the day, like humans after a long day of work.

But stories of drunk elephants on the African savannah are likely just stories, according to a 2006 study in Physiological and Biochemical Zoology. Local lore says that elephants get intoxicated from the fermented fruit of the marula tree. Elephants do have a taste for alcohol, but when scientists sat down to look at the claim, they found several problems. First, the elephants don’t eat the rotten fruit off the ground. They eat the fresh fruit right off the tree. Second, the fresh fruit doesn’t spend enough time in the elephant to ferment and produce alcohol there. And, third, even if the elephant did eat the rotten fruit, the animal would have to eat 1,400 pieces of exceptionally fermented fruit to get drunk.

The study probably won’t change the widespread belief in inebriated pachyderms, though. As the study’s lead author, Steve Morris of the University of Bristol, told National Geographic News, “People just want to believe in drunken elephants.”

Australopithecus sediba had a hand built for making stone tools (picture by Peter Schmid; courtesy of Lee Berger and the University of Witwatersrand)

Australopithecines lived in Africa some 4 million to 2 million years ago. Scientists speculate that the australopithecines gave rise to our own genus, Homo, sometime around 2 million years ago, but there’s not much fossil evidence to show exactly when or how this happened. But last year, scientists led by Lee Berger of the University of Witwatersrand announced they had found a possible candidate ancestor of Homo: Australopithecus sediba. The species lived 1.977 million years ago and resembled Homo in many ways.

This week, the researchers published five papers in the journal Science that provide a more in-depth look at the species. Experts are excited about the fossils, but do not agree on where A. sediba belongs in the human family tree—and in some sense, its discovery muddies the picture of human evolution at this critical transition 2 million years ago.

The new studies analyze two partial skeletons found in Malapa Cave in South Africa: a 12- to 13-year-old male and an adult female. Here’s a rundown of the key findings:

Brain: The researchers studied the size and shape of the young male’s brain by taking X-ray scans of his skull and creating a virtual 3-D endocast. A. sediba had a small brain—420 cubic centimeters—only slightly bigger than a chimpanzee brain or half the size of a Homo erectus brain. But the shape and organization of part of the frontal lobe appear similar to Homo. The team says this may mean brain reorganization came before a big jump in brain size in humans.

Pelvis: The pelvis had a mix of australopithecine- and Homo-like traits. This is interesting because some of A. sediba’s more advanced traits, like the shape and orientation of the ilium, were thought to have evolved in the genus Homo to accommodate bigger-brained babies as they came through the birth canal. But since A. sediba had these features and a small brain, another factor probably drove the evolution of these traits; they could be the result of spending even more time walking on the ground and less time in the trees, the researchers suggest.

Hands and Feet: The team found a nearly complete wrist and hand for the species as well as a partial foot and ankle. The foot had a unique mix of traits not seen in any other hominid, suggesting A. sediba had its own form of upright walking and probably still climbed trees. The hand also indicates A. sediba was a climber, but it shows that the hominid had the musculature and anatomy necessary for a “precision grip,” when the thumb meets the fingertips. This movement is what allows you to thread a needle or hold a pencil—and it probably enabled A. sediba to make and use stone tools, the researchers say, although they have not yet found any tools with the species.

Here’s why A. sediba complicates things. For the species to be the ancestor of Homo, it had to have lived before the first species of that genus. That’s just common sense. And it’s true for what the researchers call the “earliest uncontested evidence” of Homo: Homo erectus, at 1.9 million years ago.

But then there’s the contested evidence. At roughly 2.4 million years ago—before A. sediba— a species called H. habilis (“handy man”) lived in Africa, although the researchers say there is disagreement over what fossils should be included in this species. If this handy man is really the earliest member of Homo, it’s hard to call A. sediba an ancestor (unless, perhaps, additional fossil finds push back A. sediba’s age).

In some ways, H. habilis is more human-like than earlier hominids; it had a much larger brain, for example. But in other ways, such as the anatomy of the hand, A. sediba is more human-like than H. habilis, Berger and his colleagues say. What does this all mean? It’s unclear. But at the very least, several different types of Homo-like hominids probably all lived at about the same time—making it a “most challenging endeavor,” the researchers say, to figure out how these forms relate to each other and which if any best represents the ancestor of our genus.

As paleoanthropologists like to say, more fossils may help clarify things—or muddle them even more.

Woolly rhinos may have used their flattened horns to sweep away snow and expose edible vegetation underneath.(image by Julie Naylor)

While some scientists investigate just what caused the extinction of large mammals such as mammoths and giant ground sloths at the end of the last ice age, others are looking at the other side of things—how and where these creatures evolved. And now scientists from the Chinese Academy of Sciences and elsewhere have come up with a good possibility for the woolly rhino: Tibet. (Their study appears in this week’s issue of Science.)

A team of geologists and paleontologists found a complete skull and lower jaw of a new species of woolly rhinoceros, which they named Coelodonta thibetana, in the high-altitude Zanda Basin at the foothills of the Himalayas in southwestern Tibet. The fossil dates to about 3.7 million years ago, the middle Pliocene. The scientists posit that the woolly rhino evolved there in the cold, high-elevation conditions of Tibet and when the Ice Age began, 2.6 million years ago, it descended from its mountainous home and spread throughout northern Asia and Europe.

“The harsh winters of the rising Tibetan Plateau could well have provided the initial step toward cold adaptation for several subsequently successful members” of the group of large mammals we associate with the Ice Age, the scientists write.