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Roy L. Caldwell

Larger Pacific Striped Octopus Acts Very Social in the Lab

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Roy L. Caldwell

The octopus is not the most social species on the planet. Though they are very intelligent, they also tend to be very solitary, and they have a tendency to eat each other given the chance. They’re also incredibly secretive, hiding and camouflaging themselves to avoid predators and sneak up on their next meal, making them pretty hard to study. 

But new evidence from a group of octopuses studied in captivity indicates that the animals aren’t always so solitary. In fact, they can be downright social, cohabitating in dens and exhibiting other behaviors strikingly unusual for octopus species, as researchers report in PLOS ONE this week. The scientists—from the Monterey Bay Aquarium Research Institute, the California Academy of Sciences, and the Smithsonian Tropical Research Institute—observed 24 adult larger Pacific striped octopuses over the course of two years. 

After some of the octopuses were able to mate without eating each other (females tend to strangle and devour their mates), four pairs of octopuses were moved into communal tanks. Unusually for octopuses, these pairs mated beak-to-beak (the octopus beak is at the center of all its legs), instead of mating from a distance (using its long “special” arm). The mated pairs also spent an unusual amount of time together, with some of them even sharing a den. And the females spent an inordinate amount of time caring for their young relative to other octopuses, which often die around the time their eggs hatch. These octopuses laid eggs for up to six months and incubated them for up to eight months, laying more eggs and mating again after their first eggs had hatched.

This study confirms anecdotal evidence of similar behaviors referenced in the scientific literature from the 1970s, when the species was first being described. It suggests that we may not know the octopus as well as we think we do. However, since these behaviors were only observed in captivity among a few dozen octopuses, it remains to be seen whether wild octopuses behave in similar ways.

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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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