Crayfish get drunk faster when they’ve been hanging out with friends

Young crayfish can get drunk — and they get drunk a lot faster when they’ve been hanging out with their friends, new research says. So, extroverted crayfish may want to consider pacing themselves this weekend.

Crayfish are basically miniature, freshwater lobsters, which makes them an unusual model organism for trying to understand a behavior — drinking alcohol — that we really only care about in humans. They’re not mammals. They don’t even have backbones. But, like us, they’re social creatures, and they can get sloshed. So, a group of researchers at the University of Maryland turned to crayfish to understand how social experience changes how booze affects the brain.

The researchers gathered up a bunch of young crayfish no bigger than Cheetos and housed them in tanks with 50 to 100 friends. The scientists left one group in the communal tank right up until the experiment started, but removed the other group to house individual crayfish by themselves for about a week. Then, on the day of the experiment, the researchers moved both the communally housed and singly-housed crayfish into tanks spiked with booze, set up a camera, and stepped back to watch crayfish gone wild. It just looks a little different when a crayfish gets drunk.

First off, these little crustaceans don’t sip their cocktails, they swim in them. To get the crayfish soaked, the researchers added pure alcohol right to their tanks. And tipsy crayfish don’t slur their words, or send regrettable, late-night text messages. Instead, after swimming around in the boozy water, the crayfish adopt this upright posture, hold up their abdomens for a few seconds, and stiffly extend their legs.

The more dramatic change comes when they get a little drunker and begin crunching their abs (or, the crayfish equivalent) to flip their tails. The drunkest stage is maybe a little more familiar: when they are well and truly sozzled, the crayfish flop down on their backs, and have trouble getting back up. The drunker they get, the more the crayfish strut around upright, flip their tails, or flop over.

In crayfish, there’s a pretty well-understood circuit that’s responsible for the tail flipping, so the scientists measured how alcohol changed the excitability of the neurons in this circuit. They found in the socially-housed crayfish, alcohol made the neurons fire more easily, but had less of an effect on the loner crayfish. It’s not clear yet what, if anything, this means for people — although the researchers have more studies planned to figure out which specific neurotransmitters might be involved. But if you’re a crayfish, and you’ve been super social this week — maybe space your drinks with water tonight to avoid any embarrassing back-flopping behavior.