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Dawww. Photo: aaronz

Yellowstone National Park is a vast expanse of largely-untouched natural beauty, a tract of the Midwest home to bears and wolves and geysers and mountains. But where humankind’s direct influence is deliberately kept to a minimum, that strategy of do-no-harm doesn’t always seem to work. For the past few decades, lake trout have been taking over the rivers and lakes in Yellowstone, pushing out the local Yellowstone Cutthroat trout. The Greater Yellowstone Coalition:

Yellowstone Lake and its tributaries once supported an estimated 3.5 million Yellowstone cutthroat trout. Since the illegal introduction of lake trout in the 1980s, the cutthroat population in Yellowstone Lake has plummeted. Catch rates for Yellowstone cutthroats have significantly dropped as more and more lake trout are caught every year. The precipitous drop in cutthroat numbers is a result of lake trout predating on cutthroat trout.

But more than just affecting cutthroat trout, the invasion of the lake trout is being felt throughout the ecosystem. According to new research lead by Yale’s Arthur Middleton, the replacement of cutthroat trout with lake trout is leaving Yellowstone’s local population of grizzly bears without enough fish to eat. Middleton and colleagues:

Historically, Yellowstone Lake harboured an abundant population of cutthroat trout, but lake trout prey heavily on cutthroat trout and have driven a decline of more than 90 per cent in their numbers. Although cutthroat trout migrate up shallow tributary streams to spawn, and are exploited by many terrestrial predators, lake trout spawn on the lake bottom and are inaccessible to those predators.

Without fish, the grizzlies need something, and in their place the bears have turned to eating baby elk.

In the late 1980s, grizzly and black bears killed an estimated 12 per cent of the elk calves in northern Yellowstone annually. By the mid-2000s, bears were estimated to kill 41 per cent of calves.

The researchers say that by turning to elk calves in place of the now-gone trout, the elk population growth rate has shrunk by 2 to as much as 11 percent. The research reminds that the food web is in fact a web, and that the illegal introduction of a few trout can mean a whole lot of dead elk.

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As a patient, dealing with the anxiety of waiting to get poked with a needle may be no fun at all. But it’s actually a positive behavior. In trials with mice, stress boosted the immune system, a team of Stanford University researchers found, making it vaccines more effective. Ferris Jabr reports for Scientific American:

Mice that were stressed out prior to their inoculations had an easier time overcoming a subsequent infection than mice that the researchers left in peace before their shots.

Something similar seems to happen to people. In a study of knee surgery patients, for example, Dhabhar and his teammates found that anticipating surgery increases the number of immune cells circulating in the bloodstream in the days preceding the operation.

While stress is generally thought of in terms of its negative effects, researchers are beginning to distinguish between two different types of stress. Chronic stress, suffered over a long period of time, can cause harm, whereas acute stress, like visiting the doctor or racing to meet a deadline, may actually make us stronger and healthier.

From an evolutionary perspective, the fact that short-term stress revs up the immune system makes sense. Consider a gazelle fleeing a lioness. Once the gazelle’s eyes and ears alert its brain to the threat, certain brain regions immediately activate the famous fight-or-flight response, sending electrical signals along the nervous system to the muscles and many other organs, including the endocrine glands—the body’s hormone factories. Levels of cortisol, epinephrine, adrenaline and noradrenaline rapidly increase; the heart beats faster; and enzymes race to convert glucose and fatty acids into energy for cells. All these swift biological changes give the gazelle the best chance of escape.

The brain also responds to stress by priming the immune system to prepare for a potential injury. This may explain why people and mice more readily respond to vaccines when they’re stressed out. So cry all you’d like in the waiting room – you may be doing your body a favor in the long run.

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In the animal kingdom, larger males—think chimpanzees, lions, bulls—often try to acquire or defend more resources, like territory, food, and females, than their weaker underlings. Researchers decided to apply the competitive animal model to human political decision making about redistribution of wealth and income to see if there was any correlation.

The Atlantic describes the study:

Researchers at Aarhus University in Denmark and UC Santa Barbara collected from several hundred men and women in Argentina, the U.S., and Denmark. They categorized the subjects by socioeconomic class, their upper-body strength, or “fighting ability” (as measured by the “circumference of the flexed bicep of the dominant arm”), and their responses to a questionnaire gauging their support for economic redistribution.

They hypothesized that men with more upper body strength would be less open to wealth distribution, following the same tendency of stronger males of many animal species. After all, upper-body strength has counted as a major component of dominance throughout human evolutionary history. When economics, strength and gender were taking into account, that hypothesis turned out to be true. Popular Science reports:

Socioeconomic status also showed a correlation with economic views. As expected, rich men were generally opposed to redistribution, and poor men generally in favor of it. Men with stronger upper bodies tended to have stronger views–rich, strong men were very much opposed to redistribution, while less strong but still rich men were less opposed. On the side of those that support redistribution, the trend was reversed: poorer but strong men were strongly in favor of redistribution, while weaker poor men were not as committed.

Political party had nothing to do with the results, the researchers found, and no correlation turned up between women’s opinion on the subjet and their physical strength and/or wealth.

The authors conclude: “Because personal upper-body strength is irrelevant to payoffs from economic policies in modern mass democracies, the continuing role of strength suggests that modern political decision making is shaped by an evolved psychology designed for small-scale groups.”

For many men, apparently, animal antics still hold strong.

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In Croatia, scientists are working on a new way to detect land mines without risking lives, reports the Associated Press. Honeybees, the scientists say, have an incredible sense of smell, and with the right amount of prodding can be trained to sniff out TNT, the most common explosive used in land mines. In preliminary testing:

Several feeding points were set up on the ground around the tent, but only a few have TNT particles in them. The method of training the bees by authenticating the scent of explosives with the food they eat appears to work: bees gather mainly at the pots containing a sugar solution mixed with TNT, and not the ones that have a different smell.

A common technique in animal behavior training, the bees are taught to associate the smell of TNT with food. Once that association is firm, the bees can be turned loose in search of mines.

”It is not a problem for a bee to learn the smell of an explosive, which it can then search,” Kezic said. “You can train a bee, but training their colony of thousands becomes a problem.”

Bees, with their incredible sense of smell, light weight and ability to fly should be better candidates for mine hunting than other approaches. Mine decommissioning teams already use dogs and rats to hunt down mines. But, some anti-personnel mines are so sensitive that the weight of a pup can set them off. The bees’ training is still underway, says the AP, but if and when they’re ready the Croatian-trained bees will be able to flit from mine to mine without setting them off.

From 1999 to 2008, says the Guardian, 73,576 people reportedly died to hidden land mines or unexploded munitions. “Of these, around 18,000 were confirmed deaths – 71% of victims were civilians and 32% were children.” Aside from their destructive potential, land mines are also a psychological and social plight.

Landmines and cluster munitions have been described as “weapons of social cataclysm”, which perpetuate poverty and prevent development. They leave a legacy of indiscriminate civilian injuries and deaths, burden struggling healthcare systems and render vast tracts of land uninhabitable and unproductive. As Kate Wiggans, from the International Campaign to Ban Landmines and Cluster Munition Coalition (ICBL-CMC) says: “They keep poor people poor, decades after conflict.”

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Weee, feces! Photo: Jtu

The public pool may as well be renamed the public poo. The Centers for Disease Control and Prevention recently announced that the majority of public swimming holes have feces in them—brought to the pool on people’s unwashed skin or deposited by those who lack self-control. And along with fecal matter come illness-inducing bacteria.

Last year, the CDC tested the water from 161 public pools around Atlanta, where the CDC’s main offices are located. In 95 of them, or 58 percent, they found the bacteria Pseudomonas aeruginosa, a bacteria that causes rashes or ear infections. In 59 percent of pools they found E. coli, another sign that feces had been in the water. The CDC puts it delicately:

Fecal material can be introduced when it washes off of swimmers’ bodies or through a formed or diarrheal fecal incident in the water. The risk for pathogen transmission increases if swimmers introduce diarrheal feces.

Though the CDC only tested pools in Atlanta, they’re pretty sure that the results apply to the whole country. As the CDC tells the Associated Press, outbreaks of diarrhea are common across the country. Along with taking a pre-swim shower, the health agency wants to remind you that it’s probably a good idea to not drink the water.

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