Amphibians
Western Narrowmouth Toad
Gastrophryne olivacea · also called western narrow-mouthed toad, western narrowmouth toads
After a rare heavy rain soaks a stretch of central grassland, a western narrowmouth toad emerges from months spent hidden underground, gathering with others at a temporary pool to breed before the water disappears in the dry weeks ahead.
Overview
The western narrowmouth toad, Gastrophryne olivacea, is a small, drought-tolerant amphibian native to grassland, scrubland, and dry woodland habitat across a broad range of the central and southwestern United States. Its unusual tolerance for arid conditions, rainfall-triggered breeding strategy, and specialised ant-and-termite diet make it one of the more resilient and behaviourally specialised toads found across the American interior.
A toad that waits out the dry months underground
While its eastern relative can rely on generally moister habitat, the western narrowmouth toad has adapted to a much drier existence, spending most of the year underground and timing its entire breeding season around whatever rain happens to fall.
Status
Least Concern — widespread and common across suitable grassland, scrubland, and dry woodland habitat throughout the central and southwestern United States.
Western Narrowmouth Toad: common questions
How is the western narrowmouth toad different from the eastern narrowmouth toad?
This species tolerates far drier grassland and scrubland habitat than its closely related eastern counterpart, allowing it to persist across much of the central and southwestern United States, a considerably more arid range than the moister forest and wetland-edge habitat the eastern narrowmouth toad depends on.
Why does the western narrowmouth toad spend so much time underground?
This species spends the great majority of the year hidden underground or beneath surface debris to avoid drying out in its arid grassland and scrubland range, emerging mainly to breed after sufficient rainfall creates the temporary pools it depends on for reproduction.
When does the western narrowmouth toad breed?
This species times its breeding closely to rainfall, gathering and calling at temporary pools that form after a sufficiently heavy rain event, since these pools may not last long in the species' generally dry range, requiring eggs and tadpoles to develop quickly before the water disappears.
How does the western narrowmouth toad feed?
This species specialises heavily on ants and termites, using its small, narrow, pointed head to push into tight nest tunnels most other amphibians cannot access, the same specialised feeding strategy used by its closely related eastern counterpart.