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

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

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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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Big Questions
Why Do Cats Freak Out After Pooping?
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Cats often exhibit some very peculiar behavior, from getting into deadly combat situations with their own tail to pouncing on unsuspecting humans. Among their most curious habits: running from their litter box like a greyhound after moving their bowels. Are they running from their own fecal matter? Has waste elimination prompted a sense of euphoria?

Experts—if anyone is said to qualify as an expert in post-poop moods—aren’t exactly sure, but they’ve presented a number of entertaining theories. From a biological standpoint, some animal behaviorists suspect that a cat bolting after a deposit might stem from fears that a predator could track them based on the smell of their waste. But researchers are quick to note that they haven’t observed cats run from their BMs in the wild.

Biology also has a little bit to do with another theory, which postulates that cats used to getting their rear ends licked by their mother after defecating as kittens are showing off their independence by sprinting away, their butts having taken on self-cleaning properties in adulthood.

Not convinced? You might find another idea more plausible: Both humans and cats have a vagus nerve running from their brain stem. In both species, the nerve can be stimulated by defecation, leading to a pleasurable sensation and what some have labeled “poo-phoria,” or post-poop elation. In running, the cat may simply be working off excess energy brought on by stimulation of the nerve.

Less interesting is the notion that notoriously hygienic cats may simply want to shake off excess litter or fecal matter by running a 100-meter dash, or that a digestive problem has led to some discomfort they’re attempting to flee from. The fact is, so little research has been done in the field of pooping cat mania that there’s no universally accepted answer. Like so much of what makes cats tick, a definitive motivation will have to remain a mystery.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

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Animals
Watch a School of Humpback Whales 'Fish' Using Nets Made of Bubbles 

Just like humans, humpback whales catch many fish at once by using nets—but instead of being woven from fibers, their nets are made of bubbles.

Unique to humpbacks, the behavior known as bubble-net feeding was recently captured in a dramatic drone video that was created by GoPro and spotted by Smithsonian. The footage features a school of whales swimming off Maskelyne Island in British Columbia, Canada, in pursuit of food. The whales dive down, and a large circle of bubbles forms on the water's surface. Then, the marine mammals burst into the air, like circus animals jumping through a ring, and appear to swallow their meal.

The video offers a phenomenal aerial view of the feeding whales, but it only captures part of the underwater ritual. It begins with the group's leader, who locates schools of fish and krill and homes in on them. Then, it spirals to the water's surface while expelling air from its blowhole. This action creates the bubble ring, which works like a net to contain the prey.

Another whale emits a loud "trumpeting feeding call," which may stun and frighten the fish into forming tighter schools. Then, the rest of the whales herd the fish upwards and burst forth from the water, their mouths open wide to receive the fruits of their labor.

Watch the intricate—and beautiful—feeding process below:

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