Western Spadefoot Toads

May 5, 2017

Good news!  According to Carol Crafts, President of Friends of Goodan Ranch and Sycamore Canyon, there are many Western Spadefoot Toads (Spea hammondii) this year.  While conducting the survey on the Thornmint plant, the survey group had to watch where they were walking so that they wouldn’t tread on any of them.  The Western Spadefoot is classified as Near Threatened (NT), and is likely to qualify for a threatened category in the near future.  So this was good news indeed!

Spadefoots resemble small toads with their rounded bodies and somewhat bumpy skin. You can tell them apart from true toads by their vertical, cat-like pupils, smoother skin, and lack of enlarged parotoid glands ( a large lump) behind the eyes. They also have a hardened black digging spade on the back feet. (Some toads have a hardened growth on the back feet for digging, but it is usually not black.)

These 2-inch-long, stout-looking little toads are known for their purr-like trill, their spade-like adaptation for digging on each hind foot, and for their unusual ability to accelerate changing from a tadpole to a toad when shallow breeding pools start to dry up. 

Rarely seen, these 2 inch long, little toads are able to inhabit their hot, dry environments by burrowing underground using the hardened spades on its hind feet.  They spend most of their lives buried underground in earth-filled burrows  This Spadefoot is active for only a short period each year.    Typically between October to May, depending on rainfall, they emerge to breed and lay eggs in vernal pools.   The destruction of the vernal pools due to development is causing these creatures to lose their habitat.  Since 1950, 80% of their habitat has been destroyed.  In Southern California vernal pools can be anywhere from the size of a car tire to a football field. In San Diego County they are rarely more than six inches deep when full. For most of the year, they appear as lifeless bare spots surrounded by chaparral or disturbed coastal sage scrub. But they are vital for the breeding of the Western Spadefoot Toad. 

The adult Spadefoot feeds on insects, worms,  grasshoppers, bugs, moths, ground beetles, ladybird beetles, click beetles, spiders, flies, ants and earthworms.  It is thought to consume enough in several weeks to survive the long period they spend underground.

The call of the Western Spadefoot is truly unique.  It is a short loud trill, like a quick snore, lasting less than one second.   You can hear it at: http://www.californiaherps.com/frogs/pages/s.hammondii.sounds.html

If you see a Spadefoot, don’t pick it up!!  Skin secretions smell like peanuts, and probably deter predators. Exposure to the Western Spadefoot can cause a runny nose and watery eyes in humans.