There's a parasite in the ocean that doesn't just feed on its host, it becomes part of it — Cymothoa exigua enters a fish through the gills, kills off its tongue by cutting the blood supply, and then
The Cymothoa exigua is a parasitic isopod that enters a fish through its gills and replaces the host's tongue. It feeds on the fish's blood and mucus while effectively performing the function of the tongue for the remainder of the host's life.
Why it matters
This unique biological phenomenon provides insight into extreme parasitic evolution and the complex, often surprising, symbiotic relationships found in marine ecosystems.
When a parasite doesn't just feed on its host but replaces a vital organ, the line between predator and symbiote becomes impossibly thin.
Open the mouth of a snapper lying on a fishmonger’s ice and, every so often, something looks back. Not a tongue. A pale, plated crustacean roughly the length of a thumbnail, wedged into the floor of the mouth on seven pairs of hooked legs, sitting exactly where the tongue should be and doing more or less the tongue’s job.
That animal is Cymothoa exigua , an isopod, which makes it a saltwater relative of the woodlice under the pot plants. Its common name is the tongue-eating louse, and it is one of the few nicknames in zoology that undersells the situation.
Get smarter about the news
Sign up free for a feed built around what you actually care about, Dive Deeper research on any story, and the full text of every article.
Create free accountAlready have an account? Sign in