Western Toad

The boreal toad was once common in Yellowstone National Park.

Jeff Arnold

 

Scientific Name

Anaxyrus boreas

Identification

• 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.

Habitat

• 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.

Behavior

• 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.