Frog Research at the Museum
Discovering Frog Diversity Around the World with the Museum
For more than a century, herpetologists from the American Museum of Natural History have pioneered frog research worldwide. Expeditions to remote regions enable researchers to observe species in their natural habitats and collect specimens for further study. Museum scientists have discovered more than 160 new frog species.
Scientists from the Museum are actively engaged in conservation efforts and have contributed their expertise to the Global Amphibian Assessment Program, which is measuring extinction threats for all frog species. Museum herpetologists maintain the Amphibian Species of the World, an online catalog of the world’s living amphibians that allows scientists around the world to keep track of rapid advances in global amphibian diversity.
Found in northeastern Argentina, the Aplastodiscus perviridis frog has an elaborate mating behavior, as Museum and Brazilian herpetologists recently discovered. The male burrows into the muddy banks of streams, creating a private hideaway into which he guides his mate. After they breed, the secret basin becomes a nursery for developing tadpole larvae, which are only later carried into the stream by flash floods; the tadpoles then finish developing into frogs in the flowing water.
Two tree frogs inhabit remote areas of Bolivia, which harbor an astounding diversity of vertebrate species. Yet much of the country remains scientifically poorly documented for frogs—including the protected areas. In 2001, Raoul Bain from Museum's Center for Biodiversity and Conservation teamed up with Bolivian scientists to survey the frogs of one biological hotspot: the Amboró-Madidi corridor of the High Andes. Documenting Bolivia's frog species is a first step toward bolstering conservation efforts.
More species of amphibians live in Colombia than any other country on the planet, and scientists continue to discover new species. In 1997, Museum scientists discovered an abundant new frog species, Colostethus atopoglossus, found only on the slopes of the western Andes at El Boquerón. On a return field trip to this pristine site in 2004, researchers found no evidence of this and other previously common frog species. Were the species in hiding? Did they succumb to disease, climate change, or some as yet unknown pressure? This sort of mystery is not unique to El Boquerón. Rather it points to a growing global trend of unexplained declines in frog populations in many different regions.
Museum scientists Jay Cole and Carol Townsend, and colleagues from the University of Guyana and the Smithsonian Institution surveyed the remote Konawaruk Mountains of Guyana in the late 1990s. Access into pristine forest is often best done using boat camps, such as here along Berbice River. Species new to science abound, such as a new species of tree frog. Unfortunately, this region shares the threats faced by much of the world: habitat destruction, climate change and disease. Future monitoring of these frogs requires a baseline inventory to serve as a reference.
Washed-out roads, terrestrial leeches and days of rugged hiking can't deter Museum researcher Chris Raxworthy from exploring the northern highlands of this California-sized island. More than 200 frog species live here, 99 percent of which exist only in Madagascar. Many new species are still being discovered. Collaborating with the University of Antananarivo, the Museum is working toward a comprehensive list of the frogs on the island. One survey technique uses pitfall traps to capture secretive ground-dwelling frogs. A few species can survive without intact forest. But most others, like the newly discovered narrow-mouthed toad, are declining in Madagascar due to habitat loss, primarily forest being cleared for subsistence farming.
Visit Frog Sounds for photos and sounds of some Madagascar frogs.
The flame-red Bandiagara cliffs of Mali may appear lifeless, but toads survive in this desert landscape. These animals burrow underground or hide in rock crevasses, entering estivation (a form of hot hibernation) to escape the heat of the dry season. They also seek out water seeps in which to breed. Museum herpetologist Chris Raxworthy ventured to this relatively unexplored region in search of amphibians that are often overlooked. One such species is the Subsaharan toad, which is able to withstand the extreme climate conditions.
New housing construction throughout the Northeast provides homes for people—but sometimes at the expense of local frog populations. Herpetologists from the Museum and the Wildlife Conservation Society are knee-deep in field studies of regional wetlands, surveying the effects of development on frogs and other amphibians, such as the rare spadefoot toad. Reports of species declines have led to smarter land use practices that meet the needs of both amphibians and humans.
Papua New Guinea
Like many other frogs, the male Papua wrinkled ground frog attracts a mate using a loud vocal call. Museum researcher Richard Zweifel recorded the call of this species during one of four major surveys he conducted in Papua New Guinea. He has now described more than 50 new frog species to science. Different frog species may look very much alike, but herpetologists can analyze recordings of the calls to tell one species from another, since each has a unique call. In fact, even closely related species can have vastly different calls. Only males call; females in turn choose their mate based on a call's quality.
Waterholes, such as the one in Tarangire National Park, can often provide critical habitat for frog tadpoles. Elephants moving in and out of the pools keep researchers on their toes during collection trips to these liquid nurseries. Joined in the mid-1990s by the Wildlife Conservation Society, the University of Dar es Salaam and Tanzanian National Parks, Museum scientists Linda Ford and Michael Klemens gather frog data to better understand unusual species like the spine-covered reed frog. This information will also aid conservation management throughout the country.
Sometimes called the "Lost World," Venezuela's remote tabletop mountains remain hard for scientists to reach. But in 1995, Charles Myers and colleagues from the Museum and Fundación TERRAMAR traveled by helicopter to the mountaintops of Cerro Yaví, Guanay and Yutajé to document their unique amphibian and reptile species. The results were spectacular, including three new frog species discovered along the crags of Cerro Yaví in just five days.
Collaboration is the key to conservation in countries like Vietnam, where the known frog diversity has doubled since 1999. Struggling to keep pace with the growing threats to the country's biodiversity, especially its more than 150 amphibian species, Museum researchers Darrel Frost and Chris Raxworthy and Raoul Bain of the Center for Biodiversity and Conservation explore remote regions to document specialized frog populations. They also teach survey and collection techniques to local herpetologists. Each study reveals more biological treasures, including eight frog species discovered in 2003.
The Museum's Collection
© AMNH/D. Finnin
The Museum's oldest frog specimen dates back to 1835. Most specimens remain in jars of alcohol.
Like an immense biodiversity library, the Museum's frog collection includes more than half the world's species: over 2,500 species, ranking it as one of the five largest frog assemblages in the world. The collection allows researchers to study almost everything about frogs—including their evolutionary history, reproductive biology, and even diet—to discover their possible benefits to society and understand their conservation needs.