Leptodactylid Frogs: Leptodactylidae

Physical characteristics: Saggy skin is a very noticeable characteristic of the Patagonia frogs, but not all of them have it. Only the adults, which live in the water, develop the loose folds of skin on the sides of the body and on the thighs of the hind legs. The skin on younger frogs is not saggy. The upper side of the frog is tan to brown with tiny, darker brown speckles, and the underside is light orange. The head has a rather long snout that narrows toward the rounded tip, small eyes that face slightly forward, and eardrums that are hidden beneath folds of skin. The front legs are short and have unwebbed toes, while the longer hind In just the 10 years between 1994 and 2004, the number of Patagonia frogs fell by half, and the largest population, which lived in a lake called Laguna Blanca, has vanished completely. (Illustration by Dan Erickson. Reproduced by permission.) legs have fully webbed toes. Adults grow to 2 inches (5 centimeters) in length from the tip of the snout to the end of the rump.

Geographic range: Found only in northern Patagonia, Argentina, it lives in Laguna Blanca and small lakes in the area.

Habitat: Patagonia frogs spend most of their lives in cold, shallow, rocky-bottomed lakes, but as young frogs, they hop onto land and live under stones in tall grassy areas.

Diet: Adult Patagonia frogs eat arthropods, especially amphipods (AM-fih-pawds), that they find in the water. Amphipods are beach fleas, water lice, and other small water-living invertebrates.

Behavior and reproduction: The adult's baggy skin helps it breathe underwater. Like other frogs, the Patagonia frog can breathe through its skin. This is possible because oxygen from the water can pass right through the frog's skin and right into its blood, instead of going through the lungs first, as it does in humans. In the cold water where the Patagonia frog lives, the water has a less-than-normal amount of oxygen. With the extra folds of skin that flap in the water as the frog swims on top and between rocks on the streambed, however, the frog can take up enough oxygen to survive.

The frog's life begins when an adult female lays her small eggs on underwater plants. They hatch into golden brown tadpoles that live in the shallow water until they grow to as much as 2 inches (5 centimeters) long. They then turn into froglets that hop onto land. When they are old enough to reproduce themselves, they take to the water and develop baggy skin.

Patagonia frogs and people: People do not hunt this frog. It is not popular in the pet trade.

Conservation status: According to the World Conservation Union (IUCN), this species is Endangered, which means that it faces a very high risk of extinction in the wild. In just the 10 years between 1994 and 2004, the number of Patagonia frogs fell by half, and the largest population, which lived in a lake called Laguna Blanca, has vanished completely. Scientists blame the disappearance at Laguna Blanca on new fishes introduced into this lake. The fishes are predators of the frogs and quickly wiped out the entire population. Environmentalists fear that fishes will also be introduced into the remaining lakes and ponds where the frogs live. ∎