Leptodactylid Frogs: Leptodactylidae

Physical characteristics: With a body that is shaped like a flat, round pillow and a mouth that reaches almost from front leg to front leg, Budgett's frog is an odd-looking animal. Its head is extremely wide and has no noticeable neck to tell where the head ends and the back begins. It has two cream-colored eyes with round pupils. The eyes are set close together on top of its flat head with two nostrils below and between them on its rounded snout. Compared to its body, the four legs are quite short. The toes on its front feet are unwebbed, but those on the rear feet have webs almost to the tips. Each hind foot also has a large, black, shovel-like bump, or tubercle (TOO-ber-kul), that the With a body that is shaped like a flat, round pillow and a mouth that reaches almost from front leg to front leg, Budgett's frog is an odd-looking animal. Its head is extremely wide and has no noticeable neck to tell where the head ends and the back begins. (Illustration by Dan Erickson. Reproduced by permission.) frog uses for burrowing. Budgett's frog has an olive brown to gray back with dark blotches or pale streaks. Its underside is white. A large frog, adults usually grow to be 4.5 to 5.1 inches (11 to 13 centimeters) long from snout to rump.

Geographic range: Budgett's frog lives in the Chaco Region, a dry part of northern Argentina, southern Paraguay, and the southern half of Bolivia, which are located in central South America.

Habitat: During most of the year, Budgett's frog digs burrows in dry scrub areas and stays underground. In the breeding season, however, it comes on land and moves into shallow pools of water that dry up later in the year.

Diet: The adult diet includes snails and smaller frogs, which it finds in its pool of water. The tadpoles are also meat-eaters and eat other smaller tadpoles, which they swallow in one gulp.

Behavior and reproduction: Budgett's frog's life cycle is tied to the weather. During the long, dry season, it remains underground in burrows, but during the rainy season, it climbs onto land and into the water, where it will mate and eat a year's worth of food. After the rains end and the land begins to dry up, the frog starts digging, using its shovel-like tubercles to burrow backward into the mud on the bottom of its one-time watering hole. When it is well underground, it stops digging and sheds the outer layer of its skin. It sheds several times, and each time, the peeled-off skin piles up around the frog's body, forming a coat, or cocoon, of dead skin. This cocoon, which is waterproof, helps the frog stay moist inside. Without it, the surrounding dirt would soon soak up the frog's moisture and dry out and kill the animal.

The frog stays in its protective cocoon for about nine months when the spring rains come and wet the land again. As the water soaks the soil, the cocoon softens, and the frog crawls out of its burrow, dragging the cocoon around its body. Before doing much else, it eats its cocoon. The frog is then active for about three months— November, December, and January, which are spring and summer months in South America. If a predator approaches one of these large frogs, it faces the attacker and opens wide its gigantic mouth. In many cases, this is enough to convince the predator to find something else to eat. Once the frog becomes active in the spring, breeding starts soon. The males float in shallow pools of water and squeal their calls. Females respond, and each male mates by climbing onto a female's back and holding onto her near her front legs. A single female can lay 1,200 eggs at a time. The eggs sink in water and hatch into tadpoles in less than a day. In about 20 days, the already 2-inch-long (5.1-centimeter-long) tadpoles turn into froglets.

Budgett's frogs and people: People rarely see these frogs in the wild. They are not popular in the pet trade.

Conservation status: The IUCN does not consider this species to be at risk, but its populations in Argentina have begun to disappear. Scientists are unsure why. ∎