Watching Insects

October 17, 2009
Not Insects

This is about fish. While eating breakfast this morning, I read “A Taste for Blood” by Natalie Angier in the October/November issue of National Wildlife.

I'm sure everyone has heard the story about the candiru – a catfish that supposedly enters the urethra of people in the water in the Amazon and Orinoco Rivers. While I had heard that it was an unusual occurrence, I didn't realize that only a single instance has ever been confirmed. (Although I guess that wasn't much comfort to the only person). What really surprised me was why the fish is supposedly confused. Candiru feed in the gills of larger catfish – which they find by the scent of urine: “fish, after all, urinate from their gills.”