Octopuses are notoriously antisocial. All known 300 species live in solitude, tolerating one another only for brief periods during mating season. And when they’re not mating, they’re aggressive and surly. If you put two octopuses together in a tank they’ll usually attack each other—but not if you give them MDMA. Because as scientists discovered, high octopuses want to cuddle just like high humans do.

“Why on earth would you not be interested in what happens when octopuses take MDMA?” asked Gül Dölen, Assistant Professor of Neuroscience at John Hopkins University in Maryland. As she explained, her team wanted to know whether a famously social drug could affect a famously anti-social animal—and if so, what that might tell us about the universality of brain mechanisms.

“Octopuses only stop being asocial for brief periods of time during mating. But that said to me: Maybe they have brain infrastructure that does allow them to be social, but it’s just tuned off most of the time.”

Before the MD. Notice how the octopus on the right has its tentacles bunched up and is facing away from the other one, which is beneath the upside down basket.

The scientists chose the octopus bimaculoides, commonly referred to as the California two-spot octopus, for the study. They did so because it’s the only octopus that’s currently had its genome fully sequenced. And while the octopus bimaculoides’s overall genome sequence is roughly a 60-70 per cent match to humans, similarity between the individual genome that allows for changes in social behaviour to happen is close to a perfect match.

First, the researchers put the octopuses in a tank, where they swam around for 30 minutes. On one side of the tank was an octopus, placed under a flower pot so as to avoid any potential aggression. On the other side of the tank sat a toy. The octopuses were largely sedentary and spent most of their time with the toy.

The octopuses were then placed in a container with liquefied MDMA for 10 minutes. Twenty minutes later, when the drug’s effects were expected to take hold, they were put them back in the tank again. They then spent much more time with the other octopuses instead of the toy.

Scientists prefer to measure findings in quantitative terms: objective, measurable things like time and space. But anecdotally, Assistant Professor Dölen said, it definitely looked like the octopuses were high.

After the MD. The octopuses are spreading themselves out and interacting.

“Before the MDMA, they were very reserved. They had their arms bunched in. After the MDMA, they were super relaxed, touching and putting their mouths on everything, and hugging the flower pot with the octopus inside.

"They were in a total cuddle puddle.”

There’s currently a renaissance of scientific studies looking at how psychedelic drugs affect humans. LSD, psylocibin and MDMA are currently being studied for effects on post-traumatic stress disorder. The therapeutic effects that are being recorded are “really dramatic,” Assistant Professor Dölen said—“way higher than therapy or anti-depressants.” But more work needs to be done to work out how beneficial they might be for therapeutic purposes in the long-term.

Assistant Professor Dölen said she wants to keep studying the mechanisms of MDMA and other drugs in animals.

“In terms of a study, this has laid the groundwork for other things that we can do. There may now be opportunities to studying the impact of psychiatric drug therapies and behavioural changes in other animals distantly related to humans, not just octopus. These results are preliminary and need to be replicated in further experiments, but what we found is very cool.”

More animal species’ genomes are being sequenced each year. This progress is allowing scientists like Assistant Professor Dölen to learn more about evolutionary timelines.

“Now we can compare genomes of different species and calculate the probability of one type of change against another type of change,” she said. “This helps us to build a timeline of when animals diverged from each other, and when different genes diverged from each other. It’s a great time to be looking at evolutionary questions with these tools in hand.”

While most octopuses are generally anti-social, there’s one species of octopus, the larger pacific striped octopus, which has been confirmed as genuinely friendly. Assistant Professor Dölen said Australia’s east coast is home to another allegedly social species, the octopus tetricus. “It’s commonly found in the Sydney Harbour Bay,” she said.” Some people have claimed that octopus is actually really social, but I’m not convinced yet.”