Boreal Toad

Two toads nestled together in water

The boreal toad is the only toad species confirmed to breed in Yellowstone National Park.

Jay Fleming


Scientific Name

Bufo boreas boreas


  • Yellowstone's only toad species which is confirmed to breed in the park.
  • Adults range up to about 4 inches; juveniles just metamorphosed from tadpoles are only one 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 appear to be much rarer than spotted frogs and chorus frogs; scientists fear this species has experienced a decline in 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 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 its eyes.
  • Eaten by snakes, mammals, ravens, and large wading birds.

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