Please Don't Touch the Octopus

Posing with wild animals for social media has been a fraught topic for a while now—with quokka selfies, elephant rides, and provisioning free food all part of the conversation. Believe it or not, cephalopods are no exception.  

The petite blue-ringed octopus could easily fit in a person’s palm and its neon blue markings make it look a little cartoonish. Its small size may make it seem harmless, perhaps compelling people to pick it up and snap a pic. But the bright blue coloring says as boldly as it can: don’t touch, I’m toxic.

Blue-ringed octopuses can kill humans by biting and injecting venom. They bite when they feel threatened, and since we’re so much bigger than they are, humans are certainly threatening! Most small animals in the ocean that have stunning colors are toxic, or venomous. It’s nature’s way of warning other animals to stay clear. The venom, which is made by bacteria that live inside the blue-ringed octopus, is a neurotoxin, meaning it shuts down nerves. Most seriously, it can block the nerve impulses that control breathing in humans. People have been known to survive if they are put on a ventilator within 15 minutes of being bitten. After about 24 hours, the venom is neutralized by the victim’s body and the nerves begin to work again. The patient recovers, but getting treated in time remains a big what-if: How many beaches are within 15 minutes of a ventilator?  

Another question is whether all species of blue-ringed octopus can kill people—a hypothesis we don’t recommend testing for yourself. There are several species of blue-ringed octopuses, most of which we think are yet to be described and named. We think they live from Japan south to subtropical Australia, and east into the Indian Ocean. All blue-rings are assigned to the genus Hapalochlaena. They share iridescent blue markings scattered over their arms and mantle, the bulbous part of an octopus’s body that holds most of its organs. Some octopuses in this group don’t have rings, but lines or squiggles. 

People likely pick up these little octopuses because those bright blue warning markings aren’t always visible. When the octopus is just hanging out, its color is pretty uniform and bland. But like all octopods, it can change color (and its attitude!) in an instant, perhaps like its mood. Even more reason to admire all wildlife from a safe distance.