High tide: Give Molly to octopuses, and something strange happens

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If you give an octopus some Molly, it’ll probably ask for a cuddle.

That’s what a pair of scientists were hoping would happen, anyway, when they devised an experiment to test the effects of MDMA — also known as the psychoactive drug ecstasy or “Molly” — on octopuses.

The goal of this peculiar study, published today (Sept. 20) in the journal Current Biology, wasn’t just to see if octopuses could get high (spoiler: they sure can), but also to probe the evolutionary history of octopus behavior. Octopuses are known for being solitary, sometimes surly creatures, with one big exception — when it’s time to mate. According to the new study authors, this behavioral shift suggests that octopuses may have some neural mechanism that suppresses antisocial behavior and amplifies sexual urges when love (or at least reproduction) is in the air. [8 Crazy Facts About Octopuses]

Incidentally, similar shifts in sociability are seen in humans who have taken MDMA. That’s because MDMA is an amphetamine that increases the production of several mood-regulating neurotransmitters in the brain, including serotonin — a chemical that helps regulate happiness, appetite and sleep. Humans high on MDMA tend to be more social, more energetic, more empathetic and more euphoric than they were in their sober state. (There are also many negative, sometimes permanent health effects.)


Could it be, the researchers wondered, that octopuses evolved with a similar serotonin-uptake system that allows for the switching on and off of social behavior? To test this, the team first scoured the genome of Octopus bimaculoides (commonly known as the California two-spot octopus) to confirm the presence of serotonin transmitter genes. Then, they got several octopus test subjects high on Molly.

Rolling in the deep

In the first phase of the experiment, four male and four female octopuses (all sober) were placed one by one into a tank divided into three compartments. One compartment always contained a stationary object (sometimes a plastic flower pot, sometimes a Chewbacca or Stormtrooper action figure), the middle compartment was always empty, and a final “social” compartment contained either an unfamiliar male or unfamiliar female octopus in a plastic cage. These caged octopuses could reach out and touch the other octopuses, but did not have enough room to leave the cage or start a fight.