Undergraduate’s Study-Abroad Leads to Rediscovery

Young scientist finds frog thought to be extinct

Justin Yeager, a University of Delaware junior, had no idea his study abroad to Costa Rica would present the kind of experience a scientist can wait a lifetime for. The amateur herpetologist rediscovered the Harlequin frog (Atelopus varius), an amphibian species thought to be extinct in the tropical rainforest of that country. Tiny at 1 to 1 ½ inches long, this colorful frog species had last been seen anywhere in Costa Rica in 1996.

The discovery was a happy accident. Yeager, 21, had traveled to Latin America to study poisonous dart frogs and general herpetology at the University of Costa Rica. While there, he interacted with the locals, practicing his Spanish and teaching husbandry. It was from a local guide that Yeager first heard about an unusually colorful and poisonous toad living in the rainforest nearby. As he listened to the description of what sounded like a Harlequin, Yeager was wary. “I kept thinking, he’s got to be mistaken,” he recalls. “The species the man was describing was listed as extinct.”

Still skeptical, but with mounting excitement, Yeager asked to see the frog. Because red tape prohibited him from taking an immediate hike deep into the private rainforest reserve, the guide returned two days later with a Harlequin pair. Yeager knew immediately. The female and male frogs with the black-and-neon-orange markings had not disappeared completely. “It’s literally a second chance for this species,” he says.

Yeager contacted Federico Bolaños, a herpetologist at the University of Costa Rica, who asked the student to bring in the frogs for positive identification and documentation. A DNA sample from the tiny amphibian’s toe confirmed the Harlequin’s continued existence, and verified Yeager’s on-the-scene identification.

Yeager then placed a call to the Atlanta Botanical Gardens in Georgia, where an orchid garden had just opened. He knew that the tropical ecosystem of this garden was the ideal breeding place for Harlequins in captivity.

“Atelopus varius was common to the Costa Rican rainforest until a decade ago when a fungus resulted in their decline. More than 50 percent of the dart frog species have wiped out,” he explains.

Yeager maintains a sense of humility about his role in the frog rediscovery. “I was in the right place at the right time,” he says, adding that the future of this species is not assured.

Yeager’s frog fascination began at age 5 when he visited the National Aquarium in Baltimore. “I was mesmerized by the brightly colored dart frogs,” he says with a grin. “My parents had to pry me away from the display.”

At age 9, Yeager purchased his first dart frog. He added to his collection, breeding and selling the frogs, until his room in his Ephrata, Pa., was taken over with terrariums containing hundreds of these amphibians. Yeager was forced to move his sleeping quarters to the basement. In college, his hobby turned to passion and a new career path.

Yeager entered UD as a business major, but could not give up his interest in amphibians. He did research in the laboratory of Dr. Doug Tallamy, chair of Entomology and Wildlife Ecology in the College of Agriculture and Natural Resources. His continued fascination about the interaction and interdependence of other living organisms with these tiny creatures eventually led Yeager to a change in major from business to wildlife conservation.

“Justin is the ideal student—he’s so easy to teach,” Tallamy said. “You just point him the direction and he teaches himself.”

The future scientist holds great hope for the future of the rare species. Many questions remain about the Harlequin, he says, and further research is under way. The Atlanta Botanical Garden has sent several groups to the area to determine the number of frogs, why they have survived despite the fungus, and the feasibility of breeding them in captivity in both Costa Rica and Georgia.

Although Yeager would like to be working with them, his current goal is to finish his education. After he graduates in May 2005, he plans to pursue a doctorate so he can teach as well as continue his rainforest amphibian research. Photographs of Yeager and the Harlequin frog can be viewed on his Web site at [www.yeagersfrogs.com and clicking on the Atelopus gallery].