Overview
The Great Basin Spadefoot (Spea intermontana) is an extraordinary amphibian survivor that thrives in the bone-dry, sagebrush-dominated desert valleys of the North American Intermountain West. Equipped with sharp, black, keratinous ‘spades’ on its hind feet that allow it to burrow backward into sandy soil, this subterranean toad survives months of freezing winters and scorching summer droughts buried deep underground.
Biology and Physical Characteristics
Spea intermontana has a stout, pug-nosed, rounded body with smooth, moist, greyish-olive or tan skin marked by subtle darker blotches and fine reddish tubercles. Its most prominent features are its colossal, protruding eyes with vertical, cat-like pupils and a raised glandular boss between its eyes. On the underside of each hind foot sits a hard, sickle-shaped black keratin blade used as a digging spade.
Behavior and Ecology
A subterranean specialist, the Great Basin Spadefoot spends up to ten months of the year buried up to a meter underground in a state of water-conserving dormancy. When violent summer thunderstorms soak the desert, hundreds emerge simultaneously in the darkness, gathering at ephemeral rain pools to mate. Males emit low, duck-like snoring calls, and tadpoles develop at breakneck speed, metamorphosing in as little as 14 days before the pools evaporate.
Conservation and Human Impact
Assessed as Least Concern by the IUCN, the Great Basin Spadefoot maintains stable, widespread populations across public desert rangelands in Nevada, Utah, and Idaho. However, localized populations face threats from agricultural irrigation conversion, road mortality during mass breeding emergences, and invasive bullfrogs colonizing permanent water sources.
Interesting Factoid
The Great Basin Spadefoot can bury itself backward into loose desert sand in less than thirty seconds, using the sickle-shaped spades on its hind feet to disappear beneath the desert floor like a vanishing magician.