Some Bats Call “Dibs” on Food

In my seven-sibling family, “dibs” is the most frequently heard phrase at holiday meals. Everyone wants to lay claim to the turkey drumstick or the end piece on the ham or the last (several) beer(s) in the fridge. And it’s not just me and my brothers and sisters that warn each other to back off from our food: Scientists now think that bats do it, too. 

Researchers at the University of Maryland were examining audio recordings of big brown bats (Eptesicus fuscus) when they noticed that some of the noises the animals made were a little weird. They were unlike the sounds that bats usually use for echolocation, and turned out to be social or communicative calls, the bat version of conversation. 

One of the calls consisted of three or four long, low downward sweeps through a range of frequencies and then a few short, buzz-like calls. The “frequency-modulated bout” (FMB), as the researchers dubbed it, only seemed to be made when the bats were hunting for food. 

To learn more about the FMBs, the researchers, led by biologist Genevieve Wright, dangled a mealworm in a lab enclosure and let some bats have at it, either individually or in pairs, while they recorded things with high-speed video and audio equipment. 

The recordings revealed that only male bats emitted FMBs, and only when they were hunting with another bat. Once one bat produced an FMB, the other one quickly changed its behavior, breaking its flight path toward the food and increasing the distance between itself and the calling bat. The bat that made the noise then claimed the prey for itself. When both bats produced FMBs, the one that emitted more of the calls usually nabbed the mealworm. 

All this suggests that the FMBs have a repellent effect on nearby bats, and are the animals’ way of calling dibs on a prey item and saying “hey, that one’s mine, back off!”

The researchers are left with a nagging question, though. Why do only male bats call dibs? It might be that females don’t need to because they usually hunt alongside related bats and roost-mates, while males often forage with other, unrelated males and there is stronger competition for prey. The researchers also say its possible that only males make the FMBs because they’re related to a male-specific mating call. Even though Wright’s team only examined the calls outside of mating season, other researchers have described calls similar to the FMB being used during mating to assert control over a contested mate. 

Slow Motion Is the Only Way to Appreciate a Chameleon’s Lightning-Fast Tongue

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]

There May Be an Ancient Reason Why Your Dog Eats Poop

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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