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This Assassin Only Kills If Its Victim Strikes First

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Letting your opponent land the first blow usually isn’t a surefire strategy for winning a fight, but for one insect predator, it’s the only way to come out on top.

As their name might suggest, assassin bugs are formidable killers. They’ve got a long proboscis that they use to stab prey, inject a tissue-liquefying toxic saliva and suck the pre-digested innards out for consumption. It’s like a harpoon, syringe, and straw all in one. 

When brute strength and poison aren’t enough to make the kill or get out of trouble with their own predators, the bugs have a few other tricks. One species wears its victims’ flesh as a disguise. When it’s finished with its meals, the assassin tosses the drained carcasses onto its sticky back, building a cloak of corpses that disguises the bug and protects it from spiders. 

Another species hunts spiders instead of hiding from them, and plucks the strands of their webs to mimic the vibrations of struggling prey. When the spider rushes over expecting a meal—Pow! Toxic proboscis sneak attack!—it becomes one instead. 

Scientists have just discovered a different sort of tactic used by the species Ptilocnemus lemur, which hunts ants. It also deceives its quarry, but uses one of its own legs as a lure and lets an ant attack it before going in for the kill.

The assassin bug begins by waving one of its bristly hind legs around to attract nearby ants. Unlike all the other lurer hunters that the researchers know of, the assassin doesn’t strike when an ant gets within range, or even when it touches or grasps the bait. It just waits.

Finally, when—and only when—the ant firmly grips the bug’s leg and either attempts to sting it or drag it away, the assassin leaps into action. With the ant still hanging on to its leg, P. lemur lifts itself up and swivels 180 degrees on its “knee” joint. Now its body is above the ant, and perfectly positioned to attack a weak point in the prey’s hardened exoskeleton—a soft membrane between the head and thorax. 

Proboscis goes in. Nutritious goo comes out. 

As the researchers, led by Australian ecologist Matthew Bulbert, watched, the assassins successfully killed 81 percent of the ants that fell for their trick. In almost 500 of these attacks, though, not one assassin bug died. 

Ants are dangerous game and adept insect killers themselves. Some species are also several times bigger than the assassin bugs. Using its own leg as bait with them would seem to put the assassin in harm’s way, but Bulbert and his team think the seemingly risky strategy of letting the ant bite first actually reduces the bug's chances of getting hurt. 

By presenting its leg and waiting until the ant latches on, the assassin has tricked the ant into concentrating all its offensive traits—its size, its jaws and its venom—onto one body part. Once the ant attempts to claim its meal, its entire arsenal is occupied, and it's unable to defend itself from an quick counter-attack that comes from above and behind its head. By taking a blow to the leg, the assassin bug turns the hunter into the hunted “unopposed and essentially risk free,” the researchers say. 

Crafty and effective as it is, the strategy also has some constraints. Only 2.5 percent of the ants that the researchers saw actually grabbed the assassin bugs’ legs. But the slim chance of an ant falling for the trick, Bulbert thinks, is offset by their size. The average ant that the assassins preyed on was one to two times larger than its killers, and could feasibly provide enough food to keep an assassin going through some lean times. In some cases, the ants were as much as five times bigger than the assassin, and the bug lost all contact with the ground when it flipped over on top of its prey and had to ride on the ant’s back until it died. 

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Big Questions
Why Do Cats 'Blep'?
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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
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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.

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
Why Crows Hold Noisy Funerals for Their Fallen Friends
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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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