Dolphins Use Pufferfish as Drugs

The animal kingdom is full of surprising behaviors, but few are as strange as the apparent recreational drug use observed in dolphins. This behavior centers on the pufferfish, a creature known for its unique defense mechanism: inflating its body and releasing a potent neurotoxin. Rather than avoiding this danger, groups of young dolphins have been documented carefully and gently manipulating a pufferfish with their mouths. They seem to provoke it just enough to release small quantities of its toxin without causing serious harm to the fish or themselves, seemingly treating it with a delicacy not usually seen in predator (Review)-prey interactions.

The chemical responsible for this interaction is tetrodotoxin, a nerve toxin that is deadly in high concentrations. In the small, controlled doses the dolphins seem to be seeking, however, the toxin appears to have a narcotic effect. This remarkable behavior was first captured in detail by documentary filmmakers using spy cameras disguised as sea turtles. The footage showed the dolphins entering what looked like a trance-like state after chewing on the pufferfish. Even more fascinating was the social aspect; the dolphins would pass the pufferfish to one another, sharing the experience in a manner strikingly similar to human social rituals involving psychoactive substances.