Alyssa writes, “I’m a wildlife biology student at UC Davis with a particular obsession with ornithology, as well as a strong love for the rich, diverse ecosystems we have along the coast of northern California. Somehow seeing Brown Pelicans flying by, their bizarre combination of obvious goofiness with an odd elegance never fails to put a smile on my face. I also appreciate that (offshore oil drilling problems aside), their population growth after ESA listing is about as close to a success story as we have in conservation. My tattoo is based of a painting by one of my heroes, John James Audubon. I asked the tattoo artist to darken the hind-neck and redden the gular pouch to reflect the characteristic breeding coloration the pacific subspecies, Pelecanus occidentalis californicus. I also asked for the foliage to be removed to better reflect the roosting habitat in California. The tattoo is by Chris Arredondo at Royal Peacock Tattoo Parlor in Sacramento, CA.”

You can see the rest of the Science Tattoo Emporium here and in Science Ink: Tattoos of the Science Obsessed.

And if you live in Connecticut, you’re invited to hear me speak at the Peabody Museum of Natural History at Yale University on Thursday at 5:30. Admission is free. (Poster here.)

Originally published March 3, 2013. Copyright 2013 Carl Zimmer.

NOVA put together a video, embedded below, about one of those animals that you have to keep persuading yourself is real, a parasitic crustacean that lives inside the mouths of fishes, eating–and then taking the place of–its host’s tongue.

I can vouch for these beasts, having written about them off and on since I first encountered them in my research for Parasite Rex—most recently on the Loom last year. But I was not aware that it’s the female that wins the Oscar for best performance as a fish tongue. The males just hang out around the gills of the fish and then–yep–mate with the pseudo-tongue.

This discovery led me to wonder about the latest research about tongue-eating isopods. I came across a 2012 master’s thesis by Colt William Cook of the University of Texas, which confirms what you see in the video–that the parasites are born as males, and then when they enter a fish, one turns female. This switch only occurs if there’s no female already installed in the host–otherwise, the males stay male. As this transformation takes place, Cook adds, the female’s body grows enormously. Its eyes shrink, since it no longer has to hunt for a home. Its legs stretch out, to help it anchor itself in the mouth.

After one of the males mates with the female, she gives birth to a brood of live male parasites. For their first few days, Cook found, they search madly for another host (each species of parasite seems to only live in a single species of fish). They sniff for the scent of their host, and if a shadow passes overhead when the odor is strong, they shoot upwards through the water. They burn through a lot of energy in the process; if they fail to find a host in the first few days, they settle down and hope they can ambush a fish that happens to be swimming by. It’s a hard way to start your life, and it may explain why several males will huddle inside a fish with only a single female in the offing. Looking for another fish with a single female parasite might be a less promising strategy than competing with the males you’re with.

Of course, these rules may only apply to the species that Cook studied, which infects Atlantic croakers off the coast of Florida. The full diversity of these tongue parasites is probably enormous. A 2012 study puts the total species at 280, but that’s just known species. A team of scientists from Annamalai University in India recently did a survey of the parasites in fishes off the coast of India. Before their study, scientists knew of 47 species of parasites in Indian waters. In just nine fishes, the scientists discovered ten new parasite species. I’d wager that some of the species waiting to be discovered will prove to be even more surreal.

[Clownfish photo: Copyright Lea Lee. via Flickr ]

Originally published February 28, 2013. Copyright 2013 Carl Zimmer.