The Yosemite Toad: A Threatened Sierra Nevada Toad That Needs Snowmelt

A male Yosemite toad clasping a female during mating, a hold known as amplexus. Photo: National Park Service / Spencer Williams.

The Yosemite toad (Anaxyrus canorus) lives nowhere but the Sierra Nevada of California, and Yosemite National Park holds more than a third of its entire range. In the park it is found as high as 12,000 ft. It depends on spring snowmelt to breed.

Telling them apart

Males and females look very different — both, in their way, handsome. Females and young toads have many dark blotches on a light background. Males are a pale yellowish green or olive above, with few blotches or none. Males are also territorial, and will fight to defend their patch.

A female: dark blotches on a light background. Photo: National Park Service / Spencer Williams.

A female at the mouth of a burrow. Photo: National Park Service / Spencer Williams.

A threatened species

Populations have fallen by as much as half, and in 2014 the Yosemite toad was listed as a federally threatened species. Yosemite has been monitoring its toads across the park since 2009, so that managers can follow population trends and recommend up-to-date measures to protect them.

The decline has no single cause but many stresses adding up:

• Drying out. Tadpoles often dry up before they can finish turning into toads, because of drought brought by climate change, severe wildfires, thin winter snowpack and hotter, drier summers.
• Disease, above all the chytrid fungus.
• Pollution plays a part too.

Disease and climate change are among the threats the toads face. Photo: National Park Service / Spencer Williams & Rob Grasso.

The toad matters beyond itself: every native species helps keep an ecosystem in balance, and the Yosemite toad has its own place in the mountain food web.

How visitors can help

• Watch your step. Toads like to sit on trails.
• Do not touch one. Handling a federally listed species is illegal, and chemicals on human skin, even sunscreen, can be deadly to amphibians.
• Keep out of closed and roped-off areas. They are often closed to protect sensitive species.
• Report a sighting to the park's Aquatic Wildlife Program, and tell others about the toad.

Sources

• National Park Service, "Species in the Spotlight: Yosemite Toad," Yosemite National Park; rewritten in hubnx's own words. Photographs by the National Park Service.