Frequenters of the local zoo are advised to hold their noses and enter the amphibian house. Its residents aren't the zoo's cuddliest, but they're probably among its rarest: Amphibians have suffered not only from the usual suspects of habitat loss and global warming in recent years, but also from the rapid spread of the chytrid fungus, which infects their respiratory skin. Extinction currently threatens half the world's species.

Given the appearances of other options, researchers have chosen frogs as the flagships of their conservation efforts. Foremost among these is, as the Post reported yesterday, Amphibian Ark, which aims to preserve colonies of threatened species in zoos worldwide so that they may be reintroduced to their natural habitats after their wild brethren have suffered extinction. The Kihansi Spray Toads of the Bronx Zoo have already disappeared from Tanzania, while the National Zoo's Panamanian Golden Frogs were last seen in the wild in 2006.

Given their sensitivity, amphibians are generally considered good indicator species. Recent studies showing increased hermaphroditism in amphibians due to pesticides may mean that we humans can expect more of this guy (gal?) down the road. Extinction may be the kinder fate...

--Ben Crair