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Some Bats Call “Dibs” on Food

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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. 

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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Big Questions
Why Do Dogs Love to Dig?
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Dog owners with green thumbs beware: It's likely just a matter of time before Fido turns your azalea bed into a graveyard of forgotten chew toys. When dogs aren't digging up your prized garden, they can be found digging elsewhere in your yard, at the beach, and even between your couch cushions at home. But what exactly is behind your dog's drive to turn every soft surface he or she sees into an excavation site?

According to Dr. Emma Grigg, an animal behaviorist and co-author of The Science Behind a Happy Dog, this behavior is completely normal. "When people say 'why do dogs dig,' the first thing that always comes to mind is 'well, because they're dogs,'" she tells Mental Floss. The instinct first appeared in dogs' wolf ancestors, then it was amplified in certain breeds through artificial selection. That's why dogs that were bred to hunt rodents, like beagles and terriers, are especially compelled to dig in places where such animals might make their homes.

But this tendency isn't limited to just a few specific breeds. No matter their original roles, dogs of all breeds have been known to kick up some dirt on occasion. Beyond predatory urges, Dr. Grigg says there are two main reasons a dog may want to dig. The first is to cool off on a hot day. When stuck on an open lawn with little to no shade, unearthing a fresh layer of dirt untouched by the sun is a quick way to beat the heat.

The second reason is to stash away goodies. Imagine your dog gets bored with chewing his favorite bone but knows he wants to come back for it later. Instead of leaving it out in the open where anyone can snatch it up, he decides to bury it in a secret place where only he'll be able to find it. Whether or not he'll actually go back for it is a different story. "There's a disconnect with modern dogs: They know the burying part but they don't always know to dig it up," Dr. Grigg says.

Because digging is part of a dog's DNA, punishing your pet for doing so isn't super effective. But that doesn't mean you should stand idly by as your yard gets turned inside-out. When faced with this behavior in your own dog, one option is to redirect it. This can mean allowing him to dig in a designated corner of the yard while keeping other parts off-limits, or setting up a raised flowerbed or sandbox especially to satisfy that urge. "You can get him interested in the area by burying a couple bones or some interesting things in there for him to dig," Dr. Grigg says. "I like the idea of buried treasure."

If your dog's motive for digging is more destructive than practical, he may have an energy problem. Dogs require a certain amount of stimulation each day, and when their humans don't provide it for them they find their own ways to occupy themselves. Sometimes it's by chewing up shoes, toppling trash cans, or digging ditches the perfect size for twisting ankles. Fortunately, this is nothing more walks and playtime can't improve.

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