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Vultures Surf on Humans’ Hot Air

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A few years ago, biologists James Mandel and Keith Bildstein got a surprise while watching turkey vultures at landfill in Pennsylvania. That the birds were there wasn’t shocking—they’re scavengers, and city dumps provide a buffet of discarded meat—but their timing was. The two scientists saw the buzzards flying and feeding as late as 11 p.m., well past the time they usually call it a day and head back to their roosts. 

While their macabre eating habits and association with death might lead you to think that vultures are creatures of the night, they’re most active during the middle of the day and rarely fly after sunset. This is because of the way they fly. Like hawks, eagles, and pelicans, vultures save energy by soaring or gliding through the air instead of flapping their wings. They coast on updrafts produced by wind deflecting off the landscape and on rising columns of warm air called thermals. These air currents are strongest and most abundant in the late morning and afternoon, so that’s the schedule vultures follow: early to bed and late to rise. 

Everywhere else Mandel and Bildstein saw vultures—farms, forests, and even the suburbs around the landfill—the birds headed back to their roosts as the sun went down. At the landfill, though, they flew around well into the night. The scientists soon figured out that the vultures were able to shift their schedule thanks to man-made thermals. The landfill had four tall pipes for venting methane, which operated around the clock and created strong, hot gusts of air. When natural thermals subsided, the vultures used the vents to power late-night flights and get an altitude boost before gliding back to their roosts. The researchers also saw vultures use the vents early in the morning to gain lift before soaring off to other feeding sites. 

Now, another research team has discovered that vultures also use thermals from power plants as a pick-me-up. In Manuas, Brazil, most electrical energy is generated by group of steam-driven thermal power stations, and ecologist Weber Galvão Novaes found that vultures flock to these stations regularly. Turkey vultures, black vultures, and lesser yellow-headed vultures all used the power plants’ vent pipes for lift, and visited different stations over the course of the day. One station in a more rural area near the edge of a forest bustled with birds early in the morning and in the late afternoon and evening as the vultures used its thermals to get to and from their roosts. Another station downtown provided thermals for vultures searching for food at the city’s harbor and fish markets. 

Using mad-made thermals like this is a neat trick that shows off vultures’ adaptability, Mandel and Bildstein say, and may help explain why turkey vultures are so abundant and widespread across the Americas. But the Brazilian researchers warn that coasting over power plants could put Manua’s vultures, and its people, in harm’s way: All the power stations are close to airports, and birds congregating there could collide with planes that are coming and going. They recommend that air traffic controllers adapt to the vultures just as they’ve adapted to us, and change flight paths and schedules to avoid the power stations when there are large numbers of birds there. 

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Slow Motion Is the Only Way to Appreciate a Chameleon’s Lightning-Fast Tongue
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From the unusual way they walk, to their ability to change color, the evolutionary adaptations of chameleons are pretty bizarre, and some of them remain mysterious even to scientists. Their super-powered tongues, for instance, can dart out so quickly that the movement can barely be seen with the naked eye. But modern high-speed cameras have enabled researchers at the University of South Dakota to observe this appendage at work like never before. The video below, shared over at The Kid Should See This, includes some of that groundbreaking footage, and it's pretty amazing to watch.

Shooting at 3000 frames per second, the camera was able to capture every split-second aspect of the chameleon's tongue strike. Slowed down, the video allows you to see how every component of the process works in harmony: First, muscles in the lizard’s tongue contract like the string of a bow. Then, when that tension is released, the bony base of the tongue shoots forward, pushing the sticky, elastic part toward the chameleon’s prey.

According to Christopher Anderson, one of the scientists who conducted the high-speed camera research, larger chameleons can catapult their tongues forward at distances of one to two times their body length. For smaller chameleons, this distance can reach up to two and a half times their body length. “Small chameleons need to be able to eat more food for their body size than large chameleons,” he tells bioGraphic in the video, “and so by being able to project their tongues proportionately further than these large species, they basically are opening up additional feeding opportunities to themselves that they wouldn’t have if they had a shorter tongue.”

To see one of nature’s greatest hunting tools in action, check out the full video below.

[h/t The Kid Should See This]

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There May Be an Ancient Reason Why Your Dog Eats Poop
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Dogs aren't known for their picky taste in food, but some pups go beyond the normal trash hunting and start rooting around in poop, whether it be their own or a friend's. Just why dogs exhibit this behavior is a scientific mystery. Only some dogs do it, and researchers aren't quite sure where the impulse comes from. But if your dog is a poop eater, it's nearly impossible to steer them away from their favorite feces.

A new study in the journal Veterinary Medicine and Science, spotted by The Washington Post, presents a new theory for what scientists call "canine conspecific coprophagy," or dogs eating dog poop.

In online surveys about domestic dogs' poop-eating habits completed by thousands of pet owners, the researchers found no link between eating poop and a dog's sex, house training, compulsive behavior, or the style of mothering they received as puppies. However, they did find one common link between the poop eaters. Most tended to eat only poop that was less than two days old. According to their data, 85 percent of poop-eaters only go for the fresh stuff.

That timeline is important because it tracks with the lifespan of parasites. And this led the researchers to the following hypothesis: that eating poop is a holdover behavior from domestic dogs' ancestors, who may have had a decent reason to tuck into their friends' poop.

Since their poop has a high chance of containing intestinal parasites, wolves poop far from their dens. But if a sick wolf doesn't quite make it out of the den in time, they might do their business too close to home. A healthier wolf might eat this poop, but the parasite eggs wouldn't have hatched within the first day or two of the feces being dropped. Thus, the healthy wolf would carry the risk of infection away from the den, depositing the eggs they had consumed away in their own, subsequent bowel movements at an appropriate distance before the eggs had the chance to hatch into larvae and transmit the parasite to the pack.

Domestic dogs may just be enacting this behavior instinctively—only for them, there isn't as much danger of them picking up a parasite at home. However, the theory isn't foolproof. The surveys also found that so-called "greedy eaters" were more likely to eat feces than dogs who aren't quite so intense about food. So yes, it could still be about a poop-loving palate.

But really, it's much more pleasant to think about the behavior as a parasite-protection measure than our best pals foraging for a delicious fecal snack. 

[h/t The Washington Post]

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