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

Male Beetles Mount Other Males to Establish Dominance, Study Finds

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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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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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