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Spadefoot Toads: Pelobatidae - Behavior And Reproduction

Animal Life ResourceAmphibiansSpadefoot Toads: Pelobatidae - Physical Characteristics, Behavior And Reproduction, Conservation Status, Plains Spadefoot Toad (spea Bombifrons): Species Account - GEOGRAPHIC RANGE, HABITAT, DIET, SPADEFOOT TOADS AND PEOPLE


The spadefoot toads are burrowing frogs that spend their days and many of their nights underground where the ground is moist. They use the spades on their feet to dig rump-first into the ground. They shovel with one foot at a time and wiggle their bodies backwards into the burrow. During the rainy season, their burrows are only a couple of inches (5 centimeters) deep, but during long dry times, they may burrow down 3 feet (1 meter) or more. On rainy nights, or nights that are humid, they will come above ground to look for food. They need the moisture in the air because they can die if their skin dries out. When the soil becomes dry even deep below the surface, these frogs may snuggle inside layers of their own dead skin to keep themselves at least slightly moist and away from the dry soil, which might soak up what little moisture they have. They can survive inside these cocoons of dead skin for many weeks.

Because they stay underground much of the year, the spadefoot toads can avoid many of their predators. Even when they are above ground, the browns and grays of their skin can help to hide them from hungry eyes, especially if they stay perfectly still. If a predator does spot them, the frogs can defend themselves by sucking air into their lungs and blowing up their bodies to make them look bigger than they are. Their larger bodies might be enough to frighten away certain predators. Some species, like the eastern spadefoot toad, have skin that gives off bad-tasting and often smelly ooze that might discourage a predator. Despite all of these defense tactics, these frogs sometimes become lunch for their predators, including birds, such as owls and crows; mammals, like coyotes; and snakes.

Dangers aside, the spadefoot toads leave the protection of their underground burrows to mate on land. The sound of rain drumming on the ground overhead brings out hundreds of male spadefoot toads, which hop to puddles or shallow ponds and begin calling while floating in the water. Depending on the species, the calls may sound like crows cawing, sheep baaing, or a finger squeaking against a balloon. The calls can become quite loud, and people have reported hearing them from a mile (1.6 kilometers) away. In the water pools, the males set up territories and keep their distance from one another. The males call most at night, but may also call sometimes during the day. The females arrive and select mates. To mate, a male climbs onto a female's back and clings to her with his forelegs wrapped just in front of her hind legs. The eggs, which can number several hundred to more than a thousand per female, stream from her body and stick in clumps to underwater plants, stones, and other items. The eggs usually hatch into tadpoles within a week. If the weather is especially warm, they may hatch in just one to three days.


For many years, scientists had thought the Asian toadfrogs and spadefoot toads were so similar that they should both be placed in the same group, called a family. Closer studies revealed that the two were much more different than originally thought, and in 1985 scientists separated the toadfrogs into their own family.

Dry weather is always a threat to a tadpole, which must turn into a froglet before its watering hole evaporates. Some species, like the Plains spadefoot toad, can change into a froglet in just a few days. Usually, however, tadpoles need about one month to become froglets. Sometimes, females lay so many eggs in a small pool of water that the growing tadpoles run out of space and food. At these times, some of the tadpoles begin to eat each other, although they can recognize their littermates and do not gulp them down, too.

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