Frog Species Changes Color With Age, Sex

National Geographic News 4 Aug 09;

August 4, 2009—What's black and white and red all over? Hint: This time, it's not a newspaper.
A new frog species discovered in the Talamanca mountains of southern Costa Rica sports a range of colors depending on its gender and age.

Females are generally black with white belly splotches, such as the one pictured above. The males, meanwhile, have black, white, and brown markings peppering an orange-red base.

Young frogs of either sex are mostly brown with some beige and black blotches on their undersides.

This type of color divergence is "amazing" in the Diasporus genus of frog, the discoverers write in the May edition of the journal Zootaxa.

In fact, to "see such striking color differences between male and female frogs [in any genus] is really rare," said Valerie C. Clark, a Ph.D. student at Queen's University in Belfast, Northern Ireland, who was not involved in the research.

In general, red-and-black coloration in frogs is a red flag to predators that what they're about to eat is toxic, added Clark, a frog biologist who has received funding from National Geographic's Committee for Research and Exploration. (The National Geographic Society owns National Geographic News.)

But the chemistry of the new frog species—part of the dink frog group, so named for their bell-like calls—hasn't yet been studied, Clark said.

The newfound amphibian was "remarkably abundant" in the high-altitude rain forest where it was found. Even so, its limited habitat of fewer than 1.2 square miles (3 square kilometers) makes the frogs' survival tenuous, the study authors say.

"This study demonstrates that there is a great chance to discover new species if one takes the risk to explore remote areas," Clark added, "even within well-explored countries like the U.S.A. and Costa Rica."

—Christine Dell'Amore
Photograph courtesy Adrián García R., Museo de Zoologia, Universidad de Costa Rica