Soil Sidekicks – Eastern Spadefoots
What sounds like a sheep, digs like a champion, and uses its own foot as a shovel?
If you’re looking carefully at the ground on a rainy evening, you may be lucky enough to spot an eastern spadefoot (Scaphiopus holbrookii) digging its way back up to the surface. These fossorial (burrowing) frogs spend much of their lives underground, hiding in shallow burrows just beneath our feet.
The name Scaphiopus holbrookii originates from the Greek word skaphis, which means spade or shovel, and pous, meaning foot. The second part of the scientific name, holbrookii, honors renowned American herpetologist John Edwards Holbrook.
Eastern spadefoots are small frogs, usually between 1 and 2.5 inches long, typically shorter than the length of a finger. This North American variety of frog is plump, ranging in color from gray to brown or even almost purple. They have moist, generally smooth skin with speckles of wart-like tubercles, but don’t worry – these bumps are not contagious! Eastern spadefoots often have two mottled yellow stripes running along their backs, forming the shape of an hourglass, and bright yellow or golden eyes with vertical pupils.
The eastern spadefoot gets its name from the single black spur on the bottom of each of its hind feet. This sickle-shaped ‘spade’ enables the frog to burrow underground by wiggling back and forth, digging with its hind legs and disappearing backwards into the loose soil that the frog prefers.
These interesting amphibians live most of their lives underground, returning to the surface on occasional moist or rainy nights to hunt insects such as crickets. They also enjoy meals of spiders, worms, centipedes, snails and other creatures found in or around the soil. Eastern spadefoots are generalist feeders, happily consuming pretty much anything living that can fit into their mouths. These frogs vary in how often they return to the surface to feed, and can go a long time without eating, sometimes spending more than two weeks burrowed underground before emerging.
Eastern spadefoots can be found all over North Carolina except at particularly high elevations, but are most commonly found on the Coastal Plain or in scattered areas of the Piedmont. These frogs prefer to live in dry or semi-arid areas with loose, sandy soil to dig down into, although they can be found in soil containing more clay as well. Like all amphibians, eastern spadefoots’ semi-permeable skin allows them to absorb moisture from the soil around them, so they are good bioindicators to monitor the health of an environment – they will be among the first creatures to indicate problems such as pollutants in the ecosystem.
These burrowing amphibians remain underground for weeks during dry spells, lying dormant underground. They can curl into a tight ball and excrete fluids that harden the soil around them to retain moisture in a “pocket” in order to survive in extended droughts. If you have ever found a frog buried in your garden, especially if you live on the Coastal Plain, it may have been an eastern spadefoot.
When heavy rains begin to fall, eastern spadefoots awaken and return to the surface in an explosive congregation. These hardy amphibians breed in fishless water and temporary pools, often reproducing in water-filled ditches, tire ruts, and roadside puddles. Males drift on the surface of the water, calling for females in their high-pitched drone that resembles a sheep’s “waaaa!” Females may lay hundreds or even thousands of eggs at once, and tadpoles can undergo metamorphosis as soon as two weeks after hatching, reaching maturity in 1-2 years.
Eastern spadefoots face habitat loss in some states, but they are fairly common in North Carolina. If you find one of these creatures buried underground, leave the digging to the experts and return the Sidekick to the soil.
Soil Sidekicks is an inside scoop starring animals that live in and around the soil. Did you know that there are more living creatures in a shovelful of rich soil than there are people on the planet? Get the dirt on where the Sidekicks live and discover more about the soil that sustains us at Dig It! The Secrets of Soil.
Claire Carrington is a Museum Public Relations intern, and currently a senior at Campbell University.
Photos courtesy of Collections Manager of Herpetology, Jeff Beane.