Plains Spadefoot Toad

Description

Plains Spadefoots are a relatively small toad, at 1.38-2.36” (3.5-6 cm). Unlike the “True Toads”, they have mostly smooth skin, no parotid gland (this is the gland that produces toxins in True Toads), vertical pupils, and teeth in the upper jaw. All Spadefoot toads have a small black “spade” tubercle on the undersides of their back feet, which allow them to burrow backwards, sometimes up to almost a meter underground! They are brown to dull green. They do still have small warts, but they are not nearly as prominent as in True Toad species. They are nocturnal, and are most active at night during rain storms. It is very difficult to find them when they are not breeding and calling, due to their burrowing lifestyle. They feed on a variety of insects, including flies, moths, beetles and spiders.

Breeding occurs mostly in May, though it can linger into July. If there is a drought, the spadefoots may not breed at all that year. Females produce up to 2000 eggs in masses of 10-250 eggs, which are attached to vegetation under the surface of the water. Eggs hatch in just 2 days, and metamorphose into toadlets in just 21-34 days (this can occur even faster is more southerly parts of their range). This rapid development allows Spadefoots to capitalize on the use of temporary water bodies for breeding.

Habitat

In Alberta, Plains Spadefoot Toads are limited to the south eastern corner of the province. Because they are burrowers, they prefer loose, sandy or gravelly soil. They primarily inhabit short grass prairie, sand dunes (with and without vegetation), floodplains, and aspen parkland.

Conservation

Plains Spadefoot Toads are classed as May Be At Risk in Alberta due to habitat loss and disturbance, especially their breeding ponds. Road kill during migration to their breeding sites is also a concern. Dramatic population declines have been observed during periods of drought, which makes them susceptible weather changes due to global warming

References

Peterson Field Guides: Western Reptiles and Amphibians (3rd ed) by Robert C Stebbins.
Alberta Wildlife
Alberta Wildlife Report