This North American family contains two genera and seven species. It ranges from southern Canada to southern Mexico. For many years these frogs were placed in the Pelobatidae which contains many Eastern Hemisphere species. Recent molecular work suggests the spadefoots are the sister group to the Pelobatidae, Pelodytidae, and Megophryidae. But other workers consider them a subfamily of the Pelobatidae. Spadefoots have a black spade on each hind foot that allows them dig rapidly to hide themselves. These anurans spend most of their time underground and come to the surface to breed just after a heavy rain. They appear suddenly and disappear quickly, and are therefore said to be explosive breeders. After a heavy rain they may cover roads and be so numerous that they become a traffic hazard, making the highway excessively slippery. They are moderate in size, ranging from 35-70 mm. The skin secretions of these anurans may irritate the eyes, nose, and often the frogs have a distinctive odor when they are handled.
"Among the many kinds heard that first April night was the loud, harsh and guttural "waa, wah" of the Plains Spadefoot as hundreds of their little grayish bodies bobbed about on the wind-swept surface of a flooded field. This served as my introduction to the gnomes of the night." Arthur Bragg, 1965, Gnomes of the Night
Couch's Spadefoot, Scaphiopus couchii Baird, 1854. It inhabits short grass prairies and savanna habitats. The first photo is a male S. couchii from the vicinity of Chapala, Mexico. The second photo is female from Brewster County, TX. This species ranges from SE California to SE Colorado and SW Oklahoma, USA, southward to northern Nayarit, Zacatecas, San Luis Potosí, and northern Veracruz, Mexico. Couch's spadefoot can spend two years (possibly more) in a shallow (< 600 mm) burrow waiting for rain, the sounds of rain and probably increased soil moisture cause the spadefoots to emerge from their burrows and move to nearby breeding pools. Eggs hatch within 48 hours, and tadpoles are in a race with the drying pools to metamorphose (transform into froglets) before the pools dry up. Once the tadpoles have reabsorbed their tail they become cannibalistic, feeding on their siblings and other tadpoles in the pool
Eastern Spadefoot, Scaphiopus holbrookii (Harlan, 1835) from northern Florida. Inhabits sandy soiled forests of the eastern and southern USA. Below one emerges from sandy soil. The next photo shows the spade on the rear foot. This is the tool that allows these frogs to rapidly bury themselves in the soil. Females reach 71 mm, males 72 mm. Adults spend much of their lives in a shallow burrow and emerge to reproduce after a heavy rain (March-September). Males may call in large choruses that can be heard for a mile or more. Eggs are laid in bands on submerged vegetation, they hatch in 24-48 hours, and the tadpoles may transform within 14-60 days.
Mexican Spadefoot, Spea multiplicata (Cope, 1863) Photographed near Tucson, Arizona. Mexican Spadefoots range from southern Utah and southern Colorado to Oklahoma, Arizona, New Mexico, and West Texas south to the southern edge of the Mexican Plateau, USA, sea level to 2743 m elevation. S. multiplicta tends to use grassland habitats, but will also use desert scrub and coniferous forests. Adults reach 63 mm, making a small spadefoot species.
This animal may be the Mexican Spadefoot, Spea multiplicata (Cope, 1863) as shown above or a hybrid. It was photographed near Chapala, Mexico. Note the swelling on its back, most likely this is a parasite. In Mexico multiplicata and bombifrons may hybridize.
Plains Spadefoot, Spea bombifrons (Cope, 1863), ranges from Southern Alberta and Saskatchewan, Canada southward through Montana, North Dakota, and Nebraska and the other central plains states to Chihuahua, and Tamaulipas, Mexico. Photographed in Cochise County, Arizona. Adults reach 64 mm, making it a small spadefoot species
Great Basin Spadefoot, Spea intermontana (Cope, 1883) Photographed animal a captive from northwest Arizona.The Great Basin Spadefoot inhabits desert scrub to montane coniferous forests, and they will use agroecosystems. It spends the winter and dry months in a shallow burrow, and emerges during wet periods. It areas where this frog is abundant stomping on the ground may cause them to emerge from their burrows. Eggs are laid in a monolayer on the substrate.
