And You Think Tongue-Piercing Is Painful?

I'm not one to cite an article on this site from Cracked.com, which usually features satire and parody rather than interesting science (though I do occasionally read the site). However, an article from March caught my eye and, after looking up the sources, offers a 'scary' look at some parasitic behavior out in nature.

The article, titled The 7 Most Horrifying Parasites on the Planet (not for the squeamish), is a roundup of a few of the most extreme example of phenotypic behavior and macabre symbiotic relationships.

My favorite (least favorite?) on the list was Cymothoa exigua, whose unique survival skills would even give Darwin and Dawkins nightmares:

Cymothoa exigua is a tiny crustacean that sneaks up on a fish (specifically, a red snapper) and works its way in through the gills. Typical parasite behavior so far.

Then it attaches itself to the base of the fish's tongue, the tongue evidently being the tastiest part of the fish (get it!?). The parasite uses its claws to dig into the tongue and drink the fish's blood--and that's just the beginning.

As cymothoa exigua grows, less and less blood is able to get into the fish's tongue which causes the tongue to slowly atrophy and ultimately fall off--well, not so much "fall off" as pathetically float away, but you know what we mean.

With the tongue dead and gone, the parasite settles in and replaces the lost tongue with its own body. Somehow, cymothoa exigua is able to attach itself to the fish's tongue muscles, allowing the snapper to use it just like a normal tongue, the parasite flapping around as a permanent fixture in the fish's mouth for the rest of its life.