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Spea hammondii, the Western spadefoot toad, is medium-sized with adults reaching up to 65 mm in SVL. The skin is loose with small vertebral tubercles. The head is as wide as the body, having a rounded snout with an upward tilt and large protuberant eyes. The parotoid glands are small and not distinct. Forelimbs and hindlimbs are short and stout, with the foreleg having dorsal tubercles. The feet have well-developed webbing between the toes. The main distinguishing features are the single semicircular black "spade" (keratinized inner metatarsal tubercle) on each heel, and vertical pupils.
The dorsal ground color ranges from light green to gray with scattered darker splotches. A pair of light-colored spots is generally present, one on each side of the anus. Body tubercles can be orange to somewhat red. Usually a pair of light-colored paravertebral stripes is present, extending from behind the eyes. Ventrally, the color is whitish to creamy-yellow.
Distribution and Habitat
Country distribution from AmphibiaWeb's database: Mexico, United States
U.S. state distribution from AmphibiaWeb's database: California
Life History, Abundance, Activity, and Special Behaviors
Outside of the mating season, Spea hammondii spend most of their time underground in their burrows. The Western spadefoots are mostly nocturnal creatures, but can be heard calling during the day following winter and spring rain.
Mating occurs from late December to mid-May. Spadefoot toads are "explosive" breeders, taking rapid advantage of summer rains and ensuing temporary ponds to mate. Their mating call consists of a loud snore lasting 0.5 to 1 second, sounding like w-a-a-a or r-a-a-a-w.
A single female can lay more than 600 eggs, attaching them to vegetation. Development can be extraordinarily rapid, with hatching occurring in as little as five days. Tadpoles are light gray to dark greenish brown in color, with a cream-colored underside and a transparent tail. The larvae have a fast growth rate and can be distinguished by their tendency to hang vertically in the water and gulp air or feed on surface material. Larvae are carnivorous and have been observed preying on other species' tadpoles as well as on conspecific tadpoles. The adult diet consists mostly of arthropods.
Grismer, L. L. (2002). Amphibians and Reptiles of Baja California. University of California Press, Berkeley.
Written by Peera Chantasirivisal (Kris818 AT berkeley.edu), AmphibiaWeb Apprentice, UC Berkeley
First submitted 2005-10-11
Edited by Kellie Whittaker, Michelle S. Koo (2012-04-29)
Species Account Citation: AmphibiaWeb 2012 Spea hammondii: Western Spadefoot <http://amphibiaweb.org/species/5279> University of California, Berkeley, CA, USA. Accessed Jun 5, 2020.
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Citation: AmphibiaWeb. 2020. <http://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 5 Jun 2020.
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