Western Toad

Two toads nestled together in water
The boreal toad was once common in Yellowstone National Park.

Jeff Arnold


Scientific Name

Anaxyrus boreas


  • Yellowstone’s only toad species which is con- firmed to breed in the park.
  • Adults range up to about 4 inches, juveniles just metamorphosed from tadpoles are only 1 inch long.
  • Stocky body and blunt nose.
  • Brown, gray, or olive green with irregular black spots, lots of “warts,” and usually a white or cream colored stripe down the back.
  • Tadpoles are usually black and often congregate in large groups.


  • Once common throughout the park, now appears to be much rarer than spotted frogs and chorus frogs; scientists fear this species has experienced a decline in the ecosystem.
  • Adults can range far from wetlands because of their ability to soak up water from tiny puddles or moist areas.
  • Lay eggs in shallow, sun-warmed water, such as ponds, lake edges, slow streams, and river backwaters.


  • Tadpoles eat aquatic plants; adults eat algae, insects, especially ants and beetles, worms and other small invertebrates.
  • Sometimes active at night.
  • Defends itself against predators by secreting an irritating fluid from numerous glands on its back and behind the eyes.
  • Eaten by snakes, mammals, ravens, and large wading birds.
A tan frog with some dark spots on glistening green vegetation

Boreal Chorus Frog

Boreal chorus frogs are common with conspicuous calls.

A frog on a small log with white belly and dark green back reflected in water

Columbia Spotted Frog

To survive the winter, Columbia spotted frogs go into water that does not freeze.

Two dark green glistening salamanders with light green bellies side by side on gravel

Western Tiger Salamander

Western tiger salamanders are common and abundant in some areas of Yellowstone.

A green and brown bumpy toad in held in the hollow of two gloved hands

Plains Spadefoot Toad

In 2015, a breeding population of plains spadefoot toads was confirmed in Yellowstone.

A frog with stretched chin in water


Amphibians are valuable indicators of stressors such as disease or climate change.

Last updated: June 9, 2017

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Mailing Address:

PO Box 168
Yellowstone National Park, WY 82190-0168



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