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Male beetles tussling in their flour-floored gladiator arena. Matthew Silk
Male beetles tussling in their flour-floored gladiator arena. Matthew Silk

Male Beetles Mount Other Males to Establish Dominance, Study Finds

Male beetles tussling in their flour-floored gladiator arena. Matthew Silk
Male beetles tussling in their flour-floored gladiator arena. Matthew Silk

We believe it was the great philosophical collective Sublime who first postulated that “...[mating] and fighting; it’s all the same.” They were right—at least when it comes to flour beetles. Scientists say male broad-horned flour beetles intentionally mount other males in order to dominate them. Their findings were published in the journal Animal Behaviour.

Same-sex behavior (SSB) is incredibly common throughout the animal kingdom, but not all animals do it for the same reasons. For instance, female bonobos engage in all sorts of SSB with astonishing frequency—up to once every two hours—but primatologists say they’re not just doing it for pleasure. The bonobos have more sex when they’re stressed or social bonds are strained, which suggests that they use SSB as a tool for keeping the peace. And dog behavior experts say dogs of either sex may hump others because they feel their place in the hierarchy is threatened. 

The SSB of male broad-horned flour beetles (Gnatocerus cornutus) may be driven by a combination of these motivations, the researchers found. G. cornutus males have big jaws that they use to bite, push, and flip over their opponents during fights. After the battle, the loser typically retreats to recover, while the winner goes on to find and mate with nearby females.

The same beetles also go in for SSB, which for G. cornutus means one male beetle mounting another and drumming on his shell (the same thing they do when mating with females). Scientists suspected that the two activities served the same purpose: enforcing the pecking order. 

To find out, they set up little arenas in the lab and brought in 311 pairs of male beetles. The researchers left each pair in the arena for 20 minutes, noting both “courtship attempts” and aggression, and which beetle initiated. At the end of the round, after a 5-minute breather, they pulled out one male and brought in a female. Then, they watched for another 20 minutes, recording any courtship attempts and successful mating.

They found that 70 percent of the time, paired male beetles agreed on which beetle would be the mounter and which would be the mount-ee. In these cases, SSB was far less likely to be followed by a fight. But when the bottom beetle didn’t want to be the bottom, or tried to take a turn on top, aggression often followed. Interestingly, pairs that engaged in SSB, even if only one beetle was into it, were far less aggressive than pairs with no SSB at all.

The data also showed that mounter male beetles were more confident with female beetles, approaching them more often and having better success than mountee males. 

"Our findings provide the first empirical support for the hypothesis that same-sex sexual behaviour is an extension of male-male competition,” lead author Sarah Lane said in a press release. “They also suggest that SSB may act as a non-injurious display, allowing males to resolve dominance hierarchies without escalating into an injurious fight." 

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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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What Makes a Cat's Tail Puff Up When It's Scared?
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Cats wear their emotions on their tails, not their sleeves. They tap their fluffy rear appendages during relaxing naps, thrash them while tense, and hold them stiff and aloft when they’re feeling aggressive, among other behaviors. And in some scary situations (like, say, being surprised by a cucumber), a cat’s tail will actually expand, puffing up to nearly twice its volume as its owner hisses, arches its back, and flattens its ears. What does a super-sized tail signify, and how does it occur naturally without help from hairspray?

Cats with puffed tails are “basically trying to make themselves look as big as possible, and that’s because they detect a threat in the environment," Dr. Mikel Delgado, a certified cat behavior consultant who studied animal behavior and human-pet relationships as a PhD student at the University of California, Berkeley, tells Mental Floss. The “threat” in question can be as major as an approaching dog or as minor as an unexpected noise. Even if a cat isn't technically in any real danger, it's still biologically wired to spring to the offensive at a moment’s notice, as it's "not quite at the top of the food chain,” Delgado says. And a big tail is reflexive feline body language for “I’m big and scary, and you wouldn't want to mess with me,” she adds.

A cat’s tail puffs when muscles in its skin (where the hair base is) contract in response to hormone signals from the stress/fight or flight system, or sympathetic nervous system. Occasionally, the hairs on a cat’s back will also puff up along with the tail. That said, not all cats swell up when a startling situation strikes. “I’ve seen some cats that seem unflappable, and they never get poofed up,” Delgado says. “My cats get puffed up pretty easily.”

In addition to cats, other animals also experience piloerection, as this phenomenon is technically called. For example, “some birds puff up when they're encountering an enemy or a threat,” Delgado says. “I think it is a universal response among animals to try to get themselves out of a [potentially dangerous] situation. Really, the idea is that you don't have to fight because if you fight, you might lose an ear or you might get an injury that could be fatal. For most animals, they’re trying to figure out how to scare another animal off without actually going fisticuffs.” In other words, hiss softly, but carry a big tail.

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