You may have heard about a mako shark swimming with an orange octopus hitching a ride on its head. This behavior did surprise a lot of people. But scientists have realized it’s not unusual in the animal kingdom.

As described in “‘Sharktopus’ Wasn’t the First. These Animals Also Hitchhike on Other Animals” by Jason Bittel (https://www.nationalgeographic.com/animals/article/shark-octopus-animals-hitchhike-ride-phoresy?), this is actually quite common. There is even a name for it —  phoresy.  A review study in the journal Biological Reviews found observations of phoresy in at least 13 phyla, 25 classes, and 60 orders of animals. Other examples are the remora fish, which uses a sucker to fasten onto whale sharks, and barnacles that can be found attached to the shells of sea turtles. Actually, phoresy mostly occurs in smaller animals, especially the one that can’t travel very far on their own, like insects and other invertebrates. Sometimes it’s the best way to find a mate or complete a life cycle.

The unusual part in this example was seeing the behavior in an octopus, which usually spends its time on the seafloor. And piggybacking on a shark, which would normally consider a cephalopod a meal? Where did it think it was going?

Anyway, if you see a cockroach on an ant or a grasshopper clinging to a sheep, think nothing of it. It’s actually pretty normal.