Couch’s Spadefoot, Scaphiopus couchii
Couch’s Spadefoot, Scaphiopus couchii. Collection made in the Buenos Aires area of Los Barriles, Baja California Sur, December 2019. Length: 7.1 cm (2.8 inches). Collection and photo courtesy of Brad Murakami, Surrey, British Columbia, Canada. Identification reconfirmed by Gary Nafis, Californiaherps.com.
Couch’s Spadefoot, Scaphiopus couchii, is a member of the Scaphiopodidae family of American Spadefoot Toads. The Scaphiopodidae family consists of seven members placed in two genera. There are three species in the Scaphiopus genus. Members of the Scaphiopodidae Family differ greatly from the True Toads of the Buronidae Family by having eyes with vertical pupils, the absence of a parotid gland, and relatively smooth skin. The Couch’s Spadefoot are known in Mexico as Sapo Con Espuelas.
Couch’s Spadefoot have round bodies with short legs, protruding vertical eyes, and modified feet for digging. The underside of each rear foot has a dark elongated, sickle-shaped horny tubercle. They have a green or yellowish color that provides them with good camouflage. They display sexual dimorphism with the females growing larger in size than the males, reaching a maximum 8.9 cm (3.5 inches) in length. Females also have dark reticulations on the dorsal side of their abdomen while the males are lighter in color with faint dark spots. Tadpoles are bronze and dark gray to black in color, have eyes that are set close together and high up on their head, and reach a maximum of 3.2 cm (1.25 inches) in length.
Couch’s Spadefoot spend the majority of their time in burrows that are 20 cm (7.9 inches) to 90 cm (3 feet) deep in the soil near moisture-retaining areas for 8 to 10 months a year. They emerge during summer rainy periods and are active at night. During the day, they take shelter in burrows under dense vegetation that are up to 10 cm (3.9 inches) deep. The adults consume a wide variety of invertebrates including caterpillars, centipedes, crickets, earthworms, flies, spiders, and snails. They can consume up to 55% of their body weight, which can be enough food to last a full year. They emerge and commence breeding immediately after the first significant summer storm. Males generate loud sounds that indicate to nearby individuals that they have found a breeding pool. Their breeding pools must remain full for 8 to 10 days to complete the breeding cycle. Fertilization is external and approximately 3,000 eggs are deposited by each female. Eggs are attached to submerged vegetation in small masses. The eggs will hatch within 36 hours and the tadpoles will transform into toads in 7 to 8 days. Their larvae are subject to predation by beetles, birds, salamanders, skunk, snakes, and turtles. Additionally, their tadpoles are prone to competition for food and massive die offs without water. Tadpoles will practice cannibalism, if necessary, to survive. Metamorphosed juveniles remain in the breeding pool for a few days before moving to nearby vegetation until the soil dries up, when they burrow into the ground or take refuge in cracks or holes. On rainy nights they emerge, along with the adults, to feed until they enter a permanent refuge for the dry season. Breeding adults are between two and ten years old. Couch’s Spadefoot have life spans of up to thirteen years in the wild.
