Octopuses high on ecstasy get touchy-feely like humans, scientists discover

The notoriously anti-social octopus acts like humans after taking the drug MDMA, scientists have discovered prompting suggestions of an evolutionary link between the two species.

Researchers studied the genome of a kind of octopus not known for its friendliness toward its peers, then tested its behavioural reaction to a popular mood-altering drug also known as ecstasy.

An experiment used three connected water chambers: one empty, one with a plastic action figure under a cage and one with a female or male laboratory-bred octopus under a cage.

Four male and female octopuses were exposed to MDMA by putting them into a beaker containing a liquefied version of the drug, which is absorbed by the octopuses through their gills.

Then they were placed in the experimental chambers for 30 minutes.

Gul Dolen, assistant professor of neuroscience at the Johns Hopkins University

All four tended to spend more time in the chamber where a male octopus was caged than the other two chambers.

Under normal conditions, without MDMA, five male and female octopuses avoided only male, caged octopuses.

Gul Dolen, assistant professor of neuroscience at the Johns Hopkins University School of Medicine and the lead investigator conducting the experiments, said: "It's not just quantitatively more time, but qualitative. They tended to hug the cage and put their mouth parts on the cage.

"This is very similar to how humans react to MDMA; they touch each other frequently."

The researchers said the findings may open opportunities for accurately studying the impact of psychiatric drug therapies in many animals distantly related to people.

Prof Dolen added: "The brains of octopuses are more similar to those of snails than humans, but our studies add to evidence that they can exhibit some of the same behaviours that we can."

A summary of the experiments was published in Current Biology.