Cannibalistic Crabs Show Their Softer Side on Camera

Is it possible that murderous crustaceans have a softer side? A new video shows cannibalistic deep-sea crabs grooming one another the same way chimpanzees do.

Austinograea williamsi is not generally a snuggly critter. This pale, eyeless crab makes its home in the darkness near hydrothermal vents thousands of meters below the ocean’s surface. Its previous appearances on camera have all been a lot less aww-inspiring and a lot grislier, featuring feeding frenzies in which everyone eats everyone else’s legs.

But family members aren’t A. williamsi’s only food source. It also eats snails, anemones, and algae. Given the opportunity, it may also eat bacteria scraped off undersea surfaces. Researchers aboard the R/V Falkor believe that that may be what’s going on in this video they captured at the bottom of the Pacific Ocean thanks to a robotic submarine:

“He was literally grooming this smaller shell, just in the same way that you would see chimpanzees for instance picking bugs off of the hair of a mate,” Falkor biologist Amanda Bates told New Scientist.

Bates and her colleagues can’t say for sure why the crabs are doing it. Grooming may be a lazy way to score a snack, or it may be as much a social activity for crabs as it is for primates. Either way, Bates said, “it’s incredible to see that same type of behaviour in crabs that are 3,500 metres under the sea.”