A Guide to the Amphibians
and Reptiles of California

Spea hammondii - Western Spadefoot

Click on a picture for a larger view

Range in California: Red

Listen to this spadefoot:

A short example

More Sounds

Watch a video of this spadefoot at naturebytesvideo.com

Adult, San Joaquin County

Adult, San Diego County. © Gary Nafis
Specimen courtesy of Jim Melli San Diego Natural History Museum

Juvenile, San Joaquin County

Spade on rear foot,
San Diego County

Juvenile, San Luis Obispo County
© Andrew Harmer

Adult, Butte County
© Jackson Shedd

Adult, San Joaquin County
© Mark Gary

Adult, Kings County
© Patrick Briggs

Adult and juvenile, Kings County
© Patrick Briggs

Pale adult, San Joaquin County, © Chad Lane

Sean Powell runs across the cracked dry bed of a rain pool in San Bernardino County that was full of water in the spring and a breeding area for Western Spadefoots. After an August thunderstorm, hundreds of tiny recently-metamorphosed spadefoots, including the one shown on the right, were found emerging from cracks in the mud. © Christian Powell

Breeding

Male amplexing female underwater in daylight, San Joaquin County

Adult male calling, San Diego County
© Chris Gruenwald

Eggs

Eggs, San Joaquin County

Eggs, San Luis Obispo County
© Andrew Harmer

Egg masses found attached to spike rush at or just below the water surface at sites with depths of 18-24 inches. Large (~0.5 acre) ephemeral constructed livestock watering basin in Monterey County. Site is near an arroyo with abundant loose sandy substrate. © Pete Trenham

Tadpoles

Tadpoles feeding in a turbid rain pool, Alameda county

Tadpole, Riverside County

Recently metamorphosed juvenile with tail, Kings County © Patrick Briggs

Tadpole, Riverside County

Metamorphosing tadpole, Monterey County (captured and handled under state Scientific Collecting Permit and released at point of capture.)
© Adam Clause

Tadpole, Kings County ©Patrick Briggs

Mature tadpole, Monterey County © Rob Schell

Habitat

Brteeding habitat, slow creek, San Joaquin County

Breeding habitat, rain pools, Alameda County

Shallow breeding pool with tadpoles, San Diego County

Breeding habitat, Riverside County

Breeding pool, Butte County

Habitat, Glenn County

Breeding pool, Butte County
© Jackson Shedd

Habitat, Butte County
© Jackson Shedd

Habitat, San Joaquin County

Habitat, San Joaquin County

Breeding habitat trampled by irresponsible off-road vehicle activity, Butte County

Habitat, San Diego County

Breeding habitat, Riverside County

Short Videos

A male and a female spadefoot in amplexus underwater in a breeding area of a rocky creek bed in San Joaquin County. You can also see some eggs by the pair and floating nearby. (The first shot is of the female after the male left her.)

A tiny juvenile spadefoot, which probably transformed about 2 - 3 months earlier, is found crossing a road at night in San Joaquin County. Disturbed by our lights, it started digging into the ground in typical spadefoot fashion - using the hind legs to dig and slowly sinking down backwards to hide. But it could not dig deep enough due to the hard ground, so it hopped away into the dry grass.

Tadpoles in muddy rain puddles in Riverside County in early April.

Western Spadefoot tadpoles swim and feed in a murky rain puddle in Alameda County. The have to eat as much as possible so they will grow large enough to transform into terrestrial spadefoots before the puddle completely dries up.

Description

Size

Adults are 1.5 - 2.5 inches long from snout to vent (3.7 - 6.2 cm).

Appearance

A stout-bodied toad, greenish, brown, cream, or gray above, often with 4 irregular light stripes and dark blotches on the back,
and reddish spots at tips of skin tubercles. Unmarked and whitish below. Eyes are pale gold with vertical pupils. There is no
bump between the eyes. A glossy black spade shaped like a wedge or teardrop is present on each hind foot. The spades assist in digging soil. No parotoid glands.

Voice (Listen)

The call of the Western Spadefoot is a short loud trill, like a quick snore, lasting less than one second. Males call at night while floating on the water, often in large aggregations.

Behavior

Nocturnal. Almost completely terrestrial, entering water only to breed. This spadefoot is able to inhabit hot dry environments by burrowing underground uning the hardened spades on its hind feet. Rarely seen, spending most of its life buried underground in earth-filled burrows, and active for only a short period each year, typically between October to May, depending on rainfall. Occasionally emerges during rains at other times of the year. The burrows are probably away from the dried breeding pool.
Skin secretions smell like peanuts, and probably deter predators. They can cause a runny nose and watery eyes in humans.

Diet

Eats a variety of invertebrates, including adult beetles, larval and adult moths, crickets, flies, ants, and earthworms. Probably consumes enough in several weeks to survive the long period of underground dormancy.

Reproduction and Young

Reproduction is aquatic. Fertilization is external. Breeding takes place after heavy rainfall and the formation of temporary shallow rain pools, typically from January to May, peaking in February and March, but this spadefoot is an opportunistic breeder, physiologically capable of breeding at any time if conditions are favorable. (Ervin & Cass, 2007). Breeding typically occurs 1 - 2 days after heavy rains, sometimes as few as one or two nights each year at a particular location. There may be additional breeding during later rains. To be suitable for the successful transformation of larvae, temporary breeding pools must last for at least 30 days. If pools dry up before 30 days, larvae will not survive. Breeding sites include vernal pools and other temporary rain pools, cattle tanks, and occasionally in pools of intermittent streams.

Males are probably ready to breed 1 - 2 years after metamorphosis, females probably mature the second breeding season after metamorphosis. Adults emerge from their underground refuges and move to the breeding pool. Pools do not always occur in the same place each year, so the adults may be scattered at a distance from the pool. The loud calls of the first male to enter the pond quickly attract other males and females. During dry years, breeding pools may not form at all and breeding will not take place.

Females lay 300 - 500 eggs in irregular groups of 10 - 42 eggs, which are attached to underwater vegetation or detritus. Eggs hatch very quickly, typically in 3 - 4 days, but they may hatch anywhere from a little over half a day to 6 days later. Tadpoles transform in 4 - 11 weeks, depending on food availability and the duration of the pool. Larvae will delay transformation to take advantage of a long-lasting pool with lots of available food.

Newly transformed juveniles leave the breeding pool a few days after metamorphosis, moving at night. Where they go and how they survive the dry conditions present when they transform when rain is scarce, are not understood.

Range

Endemic to California and northern Baja California. Ranges from near Redding south throughout the Great Valley and its associated foothills, through the South Coast Ranges into coastal southern California south of the Transverse mountains and west of the Peninsular mountains, into northwest Baja California.

Habitat

Prefers open areas with sandy or gravelly soils, in a variety of habitats including mixed woodlands, grasslands, coastal sage scrub, chaparral, sandy washes, lowlands, river floodplains, alluvial fans, playas, alkali flats, foothills, and mountains. Rainpools which do not contain bullfrogs, fish, or crayfish are necessary for breeding.
From near sea level up to 4,500 ft. (1365 m) in San Diego County mountains.

Taxonomic Notes

For many years S. hammondii was grouped with spadefoots from Arizona through New Mexico into western Texas and Oklahoma, with the California subspecies called Scaphiopus hammondii hammondii.

Conservation Issues (Conservation Status)

This spadefoot has lost an extensive amount of habitat in the central valley due to urban and agricultural development of land that formerly supported the formation of temporary rain pools. It is estimated to be gone from almost 80 percent of its former habitat along the south coast. Formerly present in much of lowland southern California including the Los Angeles coastal plain, but is now absent from the area. Mosquito fish introduced into vernal pools also threaten some populations.

Taxonomy
Family	Pelobatidae	Spadefoot Toads and Relatives
Genus	Spea	Western Spadefoots
Species	hammondii	Western Spadefoot
Original Description
(Baird, 1859) - Rep. Pacif. R.R. Survey, Vol. 10, Williamson's Route, Pt. 4, No. 4, p. 12, pl. 28, fig. 2 ["1857" 1859] from Original Description Citations for the Reptiles and Amphibians of North America © Ellin Beltz
Meaning of the Scientific Name
Spea - speos - Greek for cave, cavern hammondii - honors Hammond, John F. from Scientific and Common Names of the Reptiles and Amphibians of North America - Explained © Ellin Beltz
Alternate Names
Scaphiopus hammondii hammondii - Western Spadefoot
Related or Similar California Frogs
Scaphiopus couchii Spea intermontana
More Information and References
Natureserve Explorer California Dept. of Fish and Game AmphibiaWeb Stebbins, Robert C. A Field Guide to Western Reptiles and Amphibians. 3rd Edition. Houghton Mifflin Company, 2003. Behler, John L., and F. Wayne King. The Audubon Society Field Guide to North American Reptiles and Amphibians. Alfred A. Knopf, 1992. Powell, Robert., Joseph T. Collins, and Errol D. Hooper Jr. A Key to Amphibians and Reptiles of the Continental United States and Canada. The University Press of Kansas, 1998. Bartlett, R. D. & Patricia P. Bartlett. Guide and Reference to the Amphibians of Western North America (North of Mexico) and Hawaii. University Press of Florida, 2009. Elliott, Lang, Carl Gerhardt, and Carlos Davidson. Frogs and Toads of North America, a Comprehensive Guide to their Identification, Behavior, and Calls. Houghton Mifflin Harcourt, 2009. Lannoo, Michael (Editor). Amphibian Declines: The Conservation Status of United States Species. University of California Press, June 2005. Wright, Anna. Handbook of Frogs and Toads of the United States and Canada. Cornell University Press, 1949. Storer, Tracy I. Amphibia of California, University of California Press, 1925. Davidson, Carlos. Booklet to the CD Frog and Toad Calls of the Pacific Coast - Vanishing Voices. Cornell Laboratory of Ornithology, 1995. Ervin, Edward L. and Timothy L. Cass. Herpetological Review 38 (2) 2007.

Conservation Status
The following status listings come from the Special Animals List which is published several times each year by the California Department of Fish and Game.
Organization	Status Listing
U.S. Endangered Species Act (ESA)	None
California Endangered Species Act (CESA)	None
California Department of Fish and Game	DFG:SSC	California Species of Special Concern
Bureau of Land Management	BLM:S	Sensitive
USDA Forest Service	None
Natureserve Global Conservation Status Ranks	G3 S3	Vulnerable
World Conservation Union - IUCN Red List	IUCN:NT	Near Threatened

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