This Crow’s Beak Evolved to Wield Tools

Sometimes we adapt tools to suit our purposes. Sometimes nature adapts us to suit our tools. For example: ornithologists say the bills of some crows have evolved to help them hold and manipulate their tools. The researchers published their findings in the journal Scientific Reports.

Scientists are beginning to realize that birds are much sharper than we previously realized, but even by bird-smarts standards, the New Caledonian crow (Corvus moneduloides, also known as the NCC) is special. The NCC’s ingenuity is exclusively food-driven, although their foods of choice are bugs and grubs that live in tree trunks. To extract their prey, NCCs make fishing rods and hooks by trimming excess pieces from slender sticks and barbed leaves. There’s only one other animal on Earth that makes fishing hooks: humans.

Scientists say these sophisticated behaviors are made possible by two of the crow's features: its brain and its beak. The latter's uniqueness is a new discovery, but the epiphany that inspired it is nearly 20 years old.

Ornithologist Kevin McGowan was looking at stuffed bird specimens one day in the late '90s when he noticed the NCCs. "I remember saying to a student, 'I don't know what this bird does, but it does something different from any other corvid on Earth because its bill is so weird,'" McGowan recalled in a press statement.

A few years later, in 2000, a researcher named Gavin Hunt published a paper on the NCC’s extraordinary tool use. As McGowan read the paper, a light bulb went on in his head.

Then, McGowan, Hunt, and seven of their colleagues in New Zealand and Japan decided to find out if their suspicions were right. They used computed tomography, better known as CT scanning, to make 3D images of the beaks of 11 species: NCCs, nine of their relatives, and black woodpeckers, which feed on the same in-tree grubs and bugs as the NCCs. The researchers created 11 reference points, or landmarks, so they could compare the beaks’ proportions and dimensions.

Image Credit: Matsui et al. 2016

The researchers found that McGowan was right—the shape of the NCC’s beak is completely unique. "Their bill is shorter than a regular crow's," McGowan said. "It's blunter, and it doesn't curve down like nearly all bird bills do.”

There’s a reason for that. NCCs hold their tools in their beaks, and they have perfected a technique that requires holding the stick or leaf at a specific angle. Over generations, the NCC’s beaks have obligingly curved to make this possible.

“The lower mandible actually curves slightly up, which likely gives it the strength it needs to hold the tool," McGowan said. "And because the bill doesn't curve downward it brings the tool into the narrow range of the bird's binocular vision so it can better see what it is doing."

Just like a left- or right-handed human holding a tool, each crow has a dominant side. "They hold the stick tool so that it goes up along the side of their head along the length of the bill," McGowan said. "Apparently there are birds that favor one side of the head over the other—left-sticked or right-sticked, you could call it—it’s really cool."

Big Questions
Why Do Cats 'Blep'?

As pet owners are well aware, cats are inscrutable creatures. They hiss at bare walls. They invite petting and then answer with scratching ingratitude. Their eyes are wandering globes of murky motivations.

Sometimes, you may catch your cat staring off into the abyss with his or her tongue lolling out of their mouth. This cartoonish expression, which is atypical of a cat’s normally regal air, has been identified as a “blep” by internet cat photo connoisseurs. An example:

Cunning as they are, cats probably don’t have the self-awareness to realize how charming this is. So why do cats really blep?

In a piece for Inverse, cat consultant Amy Shojai expressed the belief that a blep could be associated with the Flehmen response, which describes the act of a cat “smelling” their environment with their tongue. As a cat pants with his or her mouth open, pheromones are collected and passed along to the vomeronasal organ on the roof of their mouth. This typically happens when cats want to learn more about other cats or intriguing scents, like your dirty socks.

While the Flehmen response might precede a blep, it is not precisely a blep. That involves the cat’s mouth being closed while the tongue hangs out listlessly.

Ingrid Johnson, a certified cat behavior consultant through the International Association of Animal Behavior Consultants and the owner of Fundamentally Feline, tells Mental Floss that cat bleps may have several other plausible explanations. “It’s likely they don’t feel it or even realize they’re doing it,” she says. “One reason for that might be that they’re on medication that causes relaxation. Something for anxiety or stress or a muscle relaxer would do it.”

A photo of a cat sticking its tongue out

If the cat isn’t sedated and unfurling their tongue because they’re high, then it’s possible that an anatomic cause is behind a blep: Johnson says she’s seen several cats display their tongues after having teeth extracted for health reasons. “Canine teeth help keep the tongue in place, so this would be a more common behavior for cats missing teeth, particularly on the bottom.”

A blep might even be breed-specific. Persians, which have been bred to have flat faces, might dangle their tongues because they lack the real estate to store it. “I see it a lot with Persians because there’s just no room to tuck it back in,” Johnson says. A cat may also simply have a Gene Simmons-sized tongue that gets caught on their incisors during a grooming session, leading to repeated bleps.

Whatever the origin, bleps are generally no cause for concern unless they’re doing it on a regular basis. That could be sign of an oral problem with their gums or teeth, prompting an evaluation by a veterinarian. Otherwise, a blep can either be admired—or retracted with a gentle prod of the tongue (provided your cat puts up with that kind of nonsense). “They might put up with touching their tongue, or they may bite or swipe at you,” Johnson says. “It depends on the temperament of the cat.” Considering the possible wrath involved, it may be best to let them blep in peace.

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Why Crows Hold Noisy Funerals for Their Fallen Friends

The next time you hear a murder of crows cackling for no apparent reason, show a little respect: You may have stumbled onto a crow funeral. Crows are among the few animals that exhibit a social response to a dead member of their species. Though their caws may sound like heartbroken cries, such funerals aren't so much about mourning their fallen friends as they are about learning from their mistakes.

In the video below from the PBS series Deep Look, Kaeli Swift, a researcher at the University of Washington's Avian Conservation Lab, investigates this unusual phenomenon firsthand. She familiarized herself with a group of crows in a Seattle park by feeding them peanuts in the same spot for a few days. After the crows got used to her visits, she returned to the site holding a dead, taxidermied crow and wearing a mask and wig to hide her identity. The crows immediately started their ritual by gathering in the trees and crying in her direction. According to Swift, this behavior is a way for crows to observe whatever might have killed the dead bird and learn to avoid the same fate. Flocking into a large, noisy group provides them protection from the threat if it's still around.

She tested her theory by returning to the same spot the next week without her mask or the stuffed crow. She offered the crows peanuts just as she had done before, only this time the birds were skittish and hesitant to take them from her. The idea that crows remember and learn from their funerals was further supported when she returned wearing the mask and wig. Though she didn't have the dead bird with her this time, the crows were still able to recognize her and squawked at her presence. Even birds that weren't at the funeral learned from the other birds' reactions and joined in the ruckus.

Swift was lucky this group of crows wasn't particularly vengeful. Crows have been known to nurse and spread grudges, sometimes dive-bombing people that have harmed one of their own.

[h/t Deep Look]


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