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Biblioteca aga via Wikimedia Commons // CC BY-SA 3.0
Biblioteca aga via Wikimedia Commons // CC BY-SA 3.0

Dolphin Moms May Start Teaching Their Calves Before They're Born

Biblioteca aga via Wikimedia Commons // CC BY-SA 3.0
Biblioteca aga via Wikimedia Commons // CC BY-SA 3.0

Just as a pregnant woman may coo lovingly to her own belly, dolphin moms-to-be may talk to their calves before the little ones are even born. Speaking at the annual convention of the American Psychological Association in Denver, researchers from the University of Southern Mississippi said dolphins may start teaching their young to recognize their voices as early as two weeks before birth.

Dolphins and humans have a lot in common. Like us, they’re smart, social animals that rely heavily on sound to communicate. Each dolphin has what’s called a signature whistle: a unique noise that acts kind of like its name or call sign. Dolphin calves generally don’t come up with their own signature whistle until they’re about two months old. This may be so they can be sure they don’t choose a whistle that sounds too much like anyone else’s.

Previous studies had shown that, shortly before giving birth, pregnant dolphins start repeating their own signature whistles over and over. Some researchers theorized that the moms-to-be were trying to inspire their babies-to-be to develop their own whistles, but nobody was really sure. And while scientists had monitored moms before birth, nobody had yet continued the study after the calf was born. 

So doctoral student Audra Ames and her colleagues headed out to the dolphin enclosure at Six Flags Discovery Kingdom in Vallejo, California. A female dolphin named Bella was well into her pregnancy, and so they set up recording equipment to monitor the noises that she and others made. They captured 80 hours of sound in the four months surrounding the calf’s birth: two months before, and two months after [PDF].

Two weeks before the calf—Mirabella, or Mira—was born, Bella ramped up the amount of time she spent repeating her own signature sound, and she kept it up until Mira was two weeks old. Interestingly, at the same time, other dolphins in the enclosure quieted down, minimizing the sounds of their own names. As soon as Bella eased up on her signature sound, they went back to whistling their sounds as usual. 

Ames believes Bella was teaching Mira to recognize her mother’s voice—a form of bonding and imprinting. "We actually do see that human babies develop a preference for their mother's voice in the last trimester," she told Live Science. "We don't know if that's something that's going on here, but it could be something similar." 

That would explain the non-mom dolphins’ decision to keep it down. "What the other dolphins might be doing here is remaining quiet so the calf does not imprint on the wrong signature whistle," Ames said. 

Ames and her colleagues are currently studying other sounds made by mother-calf pairs.

[h/t Live Science]

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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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