Amphibians and reptiles are collectively known by biologists as herpetofauna. At present, there are over 5,000 described amphibian species and over 6,000 reptiles. New species in both these groups are being discovered every day, particularly in remote tropical regions that are only now being explored.

Amphibians and reptiles are also among the world's most threatened groups. The World Conservation Union (IUCN) reported in its 2003 Red List of Threatened Species that some 39 percent of surveyed reptiles and 62 percent of surveyed amphibians are imperiled. However, conservation status has yet to be assessed for numerous species—only one-fifth of reptiles and one-eighth of amphibians have been examined. The IUCN list currently includes 293 threatened reptiles and 157 threatened amphibians, up from 253 and 63 respectively in 1996. The increase in the number of listed reptiles reflects, in part, more complete examination of freshwater turtle species. Many of these are highly imperiled, particularly...