Scientists gave molly to octopus. Here is what happened.

One day in a laboratory, scientists gave MDMA to four octopuses. Do not try this at home.

After placing the eight-legged sea creatures in goblets filled with dissolved ecstasy, scientists learned that octopuses, known for their antisocial behavior, were becoming more delicate. This reaction suggests an evolutionary link between humans and octopuses through their social behavior, the scientists said.

They reported their findings Thursday in current biology.

The intelligence of the octopus competes with many mammals and the octopuses are the most behaviorally advanced invertebrates. Octopuses can complete labyrinths and escape from aquaria, but scientists previously believed that these cephalopods do not exhibit the social behaviors that often occur in smarter species.

But the new study shows that octopuses can exhibit social behaviors similar to those of humans with a slight surge of ecstasy, despite drastic differences in their brains. If combined in the future with gene sequencing, the research could reveal the evolution of social behavior between species.

Humans and octopuses have diverged in evolution 500 million years ago, and many things have changed since then. Besides the obvious additional limbs, or tentacles, lack of spine and affinity for water, octopuses have a very different central nervous system than humans. On the one hand, octopuses produce most of their nerve cells (neurons) in their arms and, therefore, can taste and touch things without their brains being involved.

In 2015, marine biologist Eric Edsinger co-discovered a surprising genetic link between octopus and humans. Genetic sequencing has revealed that octopuses and humans share an almost identical serotonin transporter, a protein that moves chemical messenger serotonin between neurons.

Serotonin transporters also intervene in the psychological changes associated with ecstasy taking.

"We were interested in the serotonin transporter because we knew that [it was] the main MDMA binding site, "said Gul Dolen, a neuroscientist at Johns Hopkins University who co-authored Edsinger's study. "If we focused on the parts of the protein that are really important for serotonin binding, then the similarity [between humans and octopuses] was over 95 percent.

Dolen and Edsinger, who work at the Marine Biological Laboratory in Massachusetts, have designed a simple experiment. They collected nine octopus species Octopus bimaculoides, exposed four invertebrates to the MDMA and observed if they became more social. They compared the behavior of these drug addicts to five sober octopuses.

In the wild, Octopus bimaculoides is only friendly for brief periods during mating. Unlike humans, laboratory mice and other mammals, octopuses do not have nucleus accumbens, folded cortex, or reward circuits – parts of the brain associated with behavioral changes due to drug use.

Molly seemed to change her behavior during the tests. When an octopus broke down interacting with its counterpart in a cage, his caresses seemed more exploratory than aggressive. This observation reflects the human behavior of becoming more social and more delicate after taking ecstasy.

Unexpected reactions of cephalopods to drugs shocked scientists who did not expect such a change in behavior.

"I found it incredibly fascinating. This fits very well with the growing idea that there are many genetic mechanisms for social behaviors that are conserved in the animal kingdom, "said Robert Meisel, a neuroscientist of the US. University of Minnesota who was not involved in the study. "You will have animals that tend to live in isolation, and by something as simple as changing a chemical in the nervous system, you can change the behavior."