Leptodactylid Frogs: Leptodactylidae

Physical characteristics: A large frog, the male South American bullfrog can grow to 7.3 inches (18 centimeters) long from snout to rump, while the female usually reaches 6.9 inches (17.6 centimeters) in length. It has a typical frog body with long, jumping hind legs, and shorter front legs. Its large head has a rounded snout with brown triangular patches on the upper lip, large eyes, and a noticeable ear drum on each side. Its head and back are usually tan to reddish brown, and two ridges run from the back of the head to the rump. Sometimes, the frog has reddish brown markings between the two ridges. The A large frog, the male South American bullfrog can grow to 7.3 inches (18 centimeters) long from snout to rump, while the female usually reaches 6.9 inches (17.6 centimeters) in length. (Illustration by Dan Erickson. Reproduced by permission.) front and back legs often have dark brown bands running across them. The toes on all four feet are unwebbed. Its underside is cream-colored with black or dark brown markings. For most of the year, the male and female look similar. During breeding season, however, the male's front legs swell, the inside toe on each front foot grows a spine, and two spines develop on each side of the chest. The large front legs and the spines help the male hold onto the female during mating.

Geographic range: This frog is found in Central and South America. It reaches as far north as Honduras in Central America and in much of northern South America, including the central and northern Amazon River basin, and parts of Ecuador and the Guianas.

Habitat: The South American bullfrog lives mainly in lowland rainforests, but it sometimes makes it home in drier forests and even slightly up the sides of mountains but below 3,800 feet (1,200 meters) above sea level. During breeding season, they move into slow-moving streams and ponds.

Diet: South American bullfrogs will eat almost anything. Adults eat large arthropods, frogs and other reptiles, and small mammals and birds. The younger bullfrogs tend to eat smaller arthropods. Tadpoles are both vegetarians and meat-eaters, gobbling up plants as well as frog eggs and tadpoles. They will even eat their own young relatives.

Behavior and reproduction: During the day, this frog hides under logs, inside burrows, or underneath leaf piles on land. Although this behavior protects it from being seen, predators sometimes spot the frog. To protect itself, the frog tries something different. It sucks in air to blow itself up to a larger size and stands as tall as it can on all four legs. The frog can also release a bad-tasting poison from its skin. Finally, as a last resort, the South American bullfrog often screams with a high voice when an attacker picks it up.

During breeding season, each male hops to water, either to the edge of a pond or a slow offshoot of a stream, and makes his loud, repeating "whoorup" calls. When a female arrives, he scoots onto her back and grasps her near her front legs. As she lays her 1,000 or so eggs, he flails his legs to whip up a foam nest. The nest lies in a dip in the ground just beyond the edge of the water. The eggs hatch into brown tadpoles about two or three days later. When rains come, the water floods the nest, and the tadpoles swim out and into the stream or pond. The tadpoles grow quickly, reaching 3.3 inches (8.3 centimeters) long, and turn into froglets when they are about a month old.

South American bullfrogs and people: Local people in some areas eat these frogs.

Conservation status: The IUCN does not consider this species to be at risk, although it is becoming rather rare in some areas where it is hunted as food. ∎