Male frog, Hyla leucophyllata, in full throat.
CREDIT: STEFEN REICHLE
By recording at night sounds emitted by frogs and then matching them to previously recorded ones, an international team of scientists is devising a new way to monitor amphibian biodiversity. Ecologist Rafael Márquez, who runs a bioacoustic lab at Madrid's National Museum of Natural Sciences, this month released two CDs with sounds from 130 Bolivian frog species, plus 36 frog choruses.
Frogs are more likely to be heard than seen, notes Márquez, so sounds are useful as "species signatures." The most common is the high-intensity male mating call, which helps females find mates of the same species. Males also have a territorial call and an alarm call. Finally, both sexes have a "release call" emitted when clasped by a male in an undesired sexual embrace.
Museum herpetologist Ignacio De La Riva and other scientists around Bolivia spent nights in the wild recording frog sounds, then playing them back in the lab to see if they matched sounds already in their database. To date, researchers have collected sounds from at least 10 hitherto undescribed species, including two that have never been seen.
