Frogs radio-tracked for first time in Madagascar

Researchers have radio-tracked frogs for the first time in Madagascar. The effort, undertaken by a group of European scientists, is detailed in the current issue of Herpetologica.

Attaching tiny radio transmitters weighing 0.3-0.35 grams (1/100 of an ounce) to 36 rainbow frogs (Scaphiophryne gottlebei), the research team tracked the movement of the colorful frogs through rugged canyons in Madagascar’s Isalo Massif. They found that the frogs have a short breeding period that occurs after the first intense rainfall at the start of the rainy season. The researchers also learned that the sexes behave similarly in terms of activity levels, and were able to confirm the preferred habitat of the species, which is listed as “Endangered” by the IUCN due to over-collection for the pet trade.

0227 radio tracking frog — A radio-tagged Scaphiophryne gottlebei individual from the Zahavola site. Photo by Gonçalo Rosa

“Our data confirm that S. gottlebei is a secretive species, hiding in sand or in holes in the canyon walls,” the authors write. “Our observations also confirm that this species is active after the first heavy rains and displays rapid breeding activity, with adult individuals continuing their activity in the canyon. We did not note any territorial behavior, but the short distances covered during dispersion suggest a strong fidelity to their original locations.”

While teasing out behavioral patterns of the endangered frog is an achievement in its own right, more importantly the study demonstrated the effectiveness of using radio telemetry on small amphibians.

“This is the first documented application of radio telemetry on a Malagasy amphibian,” note the authors. Although radio-tracking has been done previously on amphibians in Europe, those studies relied on implanted transmitters, a procedure the authors say presents unnecessary risks in a remote part of southwestern Madagascar.

“We consider this invasive technique difficult to apply when working in the field, hazardous where hygiene conditions are insufficient (and thus increases the animals’ susceptibility to septicemia), and inadequate when the species has a short breeding period like that of S. gottlebei.”