Amphibians
Western Spadefoot
Spea hammondii · also called western spadefoot toad
A western spadefoot spends most of its life buried in dry California soil, waiting. Only heavy rain draws it back to the surface, and even then the clock starts immediately: the temporary pool it breeds in may hold water for just a few weeks before it vanishes, leaving no room for a slow start.
Overview
The western spadefoot, Spea hammondii, is a burrowing toad native to grassland and dry scrub habitat across California and northern Baja California. A hardened spade on each hind foot lets it dig backward into soil within seconds, where it spends most of the year dormant.
Racing the pool
After emerging to breed in a rain-formed pool, tadpoles face a strict deadline: if the water starts drying out ahead of schedule, they can accelerate their own metamorphosis to escape as toadlets before the pool disappears entirely.
Status
Vulnerable — declining across parts of California as natural grassland and temporary vernal pool habitat is lost to agricultural and urban development.
Western Spadefoot: common questions
How does a western spadefoot dig so quickly into soil?
A western spadefoot has a hardened, sickle-shaped structure called a spade on each hind foot, which it uses to dig backward into loose soil with remarkable speed and efficiency, allowing the toad to disappear beneath the surface within seconds when conditions become too dry or a threat appears.
How long does a western spadefoot spend above ground each year?
A western spadefoot spends the great majority of the year buried underground in a dormant state, emerging above ground only for a relatively brief period following heavy seasonal rainfall, when it surfaces to feed and, if conditions are right, to breed in temporary pools before returning underground.
What happens if a western spadefoot's breeding pool dries up too fast?
Western spadefoot tadpoles are capable of accelerating their own metamorphosis when a temporary breeding pool begins drying out faster than expected, completing their development from egg to toadlet more quickly than usual in order to leave the water before it disappears completely.
Why are western spadefoot populations declining?
Western spadefoot populations have declined across significant parts of California primarily due to the loss of natural grassland and vernal pool habitat to agricultural and urban development, since the species depends specifically on temporary rain-formed pools for breeding, a habitat type that has become increasingly scarce and fragmented across much of its historic range.