Vanishing Frogs
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The Tarahumara frog disappeared from Arizona in the early 1980s. Read on to find out how scientists plan to reintroduce this vanished frog into the wild—and what you can do to help.

Stephen Hale

May 2000
U.S. biologists travel to the Sierra La Madera in northern Sonora, Mexico, and collect part of an egg mass laid by a Tarahumara frog. With appropriate permits, they take the egg mass to Fish and Wildlife Service headquarters in Phoenix, Arizona.

Stephen Hale

May 2000
Eight days later between 850 and 900 eggs hatch.

Jim Rorabaugh

June 2000
The tadpoles begin life in a ten-gallon aquarium. About half the water is replaced daily with tap water aged for 24 hours to let the chlorine disperse. At first the tadpoles eat chopped spinach and fish food. As they grow, their diet expands to include sliced cucumbers and zucchini, boiled egg whites, filamentous algae, and freeze-dried tubifex worms.

Jim Rorabaugh

July 2000
The tadpoles grow rapidly. Many are moved to foster homes, including the Arizona-Sonora Desert Museum, San Bernardino National Wildlife Refuge, Buenos Aires National Wildlife Refuge, Coronado National Memorial, and Arizona State University.

Jim Rorabaugh

August 2000
The first frogs emerge at Buenos Aires refuge 86 days after hatching. This is a surprise because biologists thought Tarahumara tadpoles took at least a year to change into frogs. Perhaps warm water and plenty of high-quality food stimulated their quick development. Only some of the tadpoles metamorphose rapidly, though. Others grow more slowly and aren’t expected to metamorphose until next spring or summer. Perhaps some tadpoles are programmed to grow more rapidly than others. Scientists have observed this adaptation in other frogs, so it may serve to improve reproductive success in a variety of environmental conditions. The young frogs vary in length from slightly less than an inch to about two inches.


October 2000
The young frogs held in aquariums are fed crickets and mealworms, while those released in semi-wild enclosures forage for themselves. Some of the outdoor frogs are now 2-1/4 inches long.

Cecil Schwalbe

December 2000
About 350 frogs and tadpoles are still alive. Some of those in outdoor enclosures have fallen victim to giant water bugs (up to four inches long) like the one in the photo, which is devouring a metamorphosed northern casque-headed frog. Because all these frogs came from a single egg mass, biologists will need to collect more egg masses from the wild to establish a healthy breeding population. Even with these additions, the frogs will be bred selectively to increase genetic diversity. Producing egg masses and tadpoles in captivity will reduce the need to remove frogs from the wild.


The Tarahumara Frog Conservation Team, a consortium of interested citizens, researchers, and government wildlife and land managers, has developed a plan to reintroduce the Tarahumara frog into at least two of its former homes in Arizona—Big Casa Blanca Canyon in the Santa Rita Mountains and Sycamore Canyon in the Pajarito Mountains. Once the Arizona Game and Fish Commission approves the plan, the captive frogs will be released this summer.

The Tarahumara frog needs your help! Approval isn’t a sure thing. Some people don’t want another rare species in their “backyard.” Others fear that reintroduction might threaten livestock grazing, mining, and recreation, even though these activities didn’t contribute to the frog’s disappearance.

If you support the reintroduction, please write to the following officials to urge prompt approval and implementation of the conservation plan:

W. Hays Gilstrap
Arizona Game and Fish Commission
2221 West Greenway Road
Phoenix, Arizona 85023-4399

Susan Chilton (the reintroduction sites are in her district)
Arizona Game and Fish Commission
2221 West Greenway Road
Phoenix, Arizona 85023-4399

Duane Shroufe
Arizona Game and Fish Department
2221 West Greenway Road
Phoenix, Arizona 85023-4399

TARAHUMARA FROG (Rana tarahumarae)

Stephen Hale

Small, dark spots on its body and dark crossbars on its legs distinguish this drab green-brown, medium-size (2.5-4.5 inches from nose to rear) frog. Because it lives in the water, its hind feet are extensively webbed. Both males and females call—a low grunt that lasts about half a second.

Stephen Hale

Until the early 1980s, Tarahumara frogs ranged from the Sierra Madre Occidental northwestern Mexico (southwestern Chihuahua, eastern Sonora, and northern Sinaloa) into the Santa Rita and Atascosa-Parajarito Mountains of southernmost Arizona. The last Tarahumara frog in Arizona was spotted in 1983 in the Santa Ritas. Today they are most plentiful in the mountains of eastern Sonora (see photo).

Habitat: Streams and deep plunge pools in pine-oak woodland, thorn scrub, and tropical deciduous forest.

Tarahumara frogs feed on a wide variety of prey items, including fish, juvenile mud turtles, snakes, beetles, moths, water bugs, scorpions, centipedes, grasshoppers, mantids, wasps, spiders, crickets, caddis flies, and katydids. In turn, Tarahumara frogs are probably eaten by ringtail cats, birds, snakes (especially garter snakes), other frogs, rosy salamanders, fish, and water bugs and other invertebrates.

Tarahumara frogs favor pools in steep canyon streams as breeding sites. The greenish yellow, spotted tadpoles grow as long as 3.8 inches before turning into frogs.

Status in Arizona
Last seen in the wild in May 1983.

Possible culprits in disappearance from Arizona
Climate change (flooding, severe drought, colder winter)
Introduced aquatic predators
Pollution (acid rain, heavy metal poisoning)