Boreal Toad (Anaxyrus boreas boreas)

fat, dark green toad sits on a sunny log

Boreal Toad (Anaxyrus boreas boreas)

The Boreal Toad (Anaxyrus boreas boreas) is a protected species in Wyoming that prefers mountainous areas at high elevations between 7,000-12,000 ft, and this pictured toad was found on the shore of Swan Lake in Grand Teton National Park (GTNP). Populations have been on the decline over the past 20 years due to chytrid fungus—an infectious fungus among amphibians that causes a deadly disease. The fungus is currently being studied all over Wyoming amphibious habitats and in other states that have listed the Boreal Toad as endangered, like Colorado and New Mexico. Specifically, in the Greater Yellowstone Ecosystem (GYE), their populations have declined since studies in the 1950s. There is enough concern that a genetic bank and translocation efforts for these little guys is held in the Colorado Parks and Wildlife’s Native Aquatic Species Restoration Facility.

Adult Boreal Toads can be anywhere from 2.5-4 inches long, and young toads often lack the distinct light-colored stripe down the middle of their back. Tadpoles hatch late May to late June when they will start their two-month transition to toadlets. Toad skin is rough and bumpy which is the opposite of a frog. Young Boreal Toads generally are diurnal, and adults are mostly nocturnal. During spring and summer, you might find Boreal Toads by water—preferably acidic water for breeding. In winter, they hibernate underground in burrows, but the rest of the year they spend about a fourth of their time burrowing and then the remainder living in forested areas. These toads live in both dry and wet areas when not breeding, but usually near water. If you are looking for a Boreal Toad during mating season and expect to hear a loud chorus call, you may not hear anything because males have no vocal sac that other amphibians attract females with. Instead, they can muster up quiet calls to say they are disturbed. People have compared their call to a tiny chirp!

Written by Celia Karim
PC: Anne Guzzo