LEPTODACTYLID FROGS: Leptodactylidae

PHYSICAL CHARACTERISTICS

With more than 1,100 species of leptodactylid frogs, this is a huge family that has many different-looking species. The smallest species grow only to 0.4 inches (1 centimeter) long from the tip of the snout to the back of the rump, while female helmeted water toads can reach as much as 12.8 inches (32 centimeters) long. Many species in this family have toadlike features, including short legs and warty backs, while others have the look of a typical frog with long, jumping hind legs and smooth skin on their backs. Some have chunky bodies, some are slender, and a few are quite flat. Some of the more unusual members of this family have very baggy skin that hangs in folds from their sides and the upper part of each hind leg, and others have fleshy points, or "horns," on the eyelids.

Although they may look different on the outside, they do share some common features. For example, most of the leptodactylid frogs have teeth on the upper jaw, as well as horizontal pupils in their eyes. A few have vertical pupils. The bones at the tips of the toes of all species in this family either are T-shaped or have knobs. In some species, small pads cover the tips and help the frog to climb up slippery rocks or tall trees. Most species in this family are gray, green, or brown and blend into the background.

A few, however, have bright patterns. The gold-striped frog, for instance, is black with bright yellow stripes. Scientists think that these bright colors trick predators into thinking the gold-striped frog is actually a species of poison dart frog that is also black with yellow stripes. Predators will not eat the poison dart frog, because it oozes a poison from its skin, and may also avoid the look-alike species, even though it is harmless. In addition to its copycat color, the gold-striped frog has red "flash colors" at the tops of its legs. When threatened, this frog and some other species in the family that have similar bright patches move their legs so these spots show. This sudden burst of color may surprise a predator and give the frog time to escape. The gray four-eyed frog has another feature on its back that can scare off attackers. When threatened, it rounds its lower back to show off two large, dark-colored glands. This display gives the impression that a larger animal with two big eyes has suddenly appeared.

Males and females usually look alike. In some species, however, the males develop spines on the front toes and/or chest during the breeding season. These spines help the male ride piggyback and hold onto the female during mating. The males of many species in this family grab the female around her front legs, but some hold her near her back legs while she lays her eggs.

GEOGRAPHIC RANGE

These frogs live in North, Central, and South America, as well as the West Indies. In North America, they can be found in Mexico and southernmost parts of the United States. One species, the gray four-eyed frog, lives farther south than any other species in the world: the Straits of Magellan at the southern tip of South America.

HABITAT

These frogs may live almost anywhere from hot and humid valleys and lowland forests to cooler, drier land high up in the mountains. Depending on the species, they may spend much of their time hiding under rocks or other places on land, hopping through grass or forests, climbing in trees, or swimming under water. Some even live in burrows inside ant hills. Mating in the typical leptodactylid frog happens in the water. This may be a lake, small pond, a pool that is only filled with water during part of the year, or some other body of water.

DIET

Most of the species in this family get their food by finding a promising spot and waiting there for a meal to come to them. This kind of sit-and-wait method is called ambush hunting. Many of the species in this family have colors and patterns that make them almost disappear from view if they remain very still. Many leptodactylid frogs eat arthropods (AR-thro-pawds), which are spiders, insects, and other invertebrates with jointed legs. An invertebrate (in-VER-teh-breht) is an animal without a backbone. Some of the larger species, like the Surinam horned frog and South American bullfrog, will eat almost anything that they can capture and swallow, including other frogs, snakes, and even small birds and mammals.

BEHAVIOR AND REPRODUCTION

Although some species in this family are active during the daytime, most of them usually stay out of sight while the sun is shining and move about after dark. During the day, they typically hide under rocks or logs, inside dark cracks and burrows, or tucked into the leaves of plants. Some of the species, like the Surinam horned frog, have camouflage colors and eyebrow "horns" that help the frog to look like a leaf when it is nestled in a pile of dead leaves on the ground. Most leptodactylid frogs do their hunting at night.

To protect themselves against predators, the majority of the frogs in this family simply try to hop away. Others will stay still and hope their camouflage is good enough to keep them hidden. If an attacker comes too close, some species will use other defensive methods. For example, the helmeted water toad takes a big gulp of air to blow up its body, stands up as tall as possible on all four legs, opens wide its mouth, and snaps at the attacker. Since males of this species can reach 4.8 inches (12 centimeters) long, and females can grow to a whopping 12.8 inches (32 centimeters), they can convince many predators to back off.

Some leptodactylid frogs that live in areas with particularly dry seasons survive the weather by burrowing into the mud left on the bottom of disappearing pools of water. Budgett's frog is an example. It digs deep in the mud until it is completely covered, then sheds its outer layers of skin, which it wears like a blanket around its body. The dead skin cocoon helps the frog to stay moist inside during the dry period, which may last many weeks. When the rainy season returns, the water drenches the ground, softens up the cocoon, and the frog crawls out of its burrow.

Many of the frogs that live in climates with both dry and wet seasons mate in the rainy season. Some of those that live in areas that are wet and warm all year may mate during only a short time each year, or they may mate off and on all year long. Regardless of when they mate, they kick off a mating period with the calls of the males. Some, like the Cururu lesser escuerzo, call from water, but Perez's snouted frog and others call from their hiding places on land. Some males, including gray four-eyed frogs, do not call. When a female approaches, the male typically climbs onto her back and hangs on by either clinging to her at her front legs or in front of her hind legs. This piggyback position is called amplexus (am-PLEK-sus). Those frog pairs that are on land hop and crawl over to the water. Those that are already in the water mate there. While the male is still on her back, the female lays her eggs.

The females of some species, like the warty tree toad, drop their eggs in the water, and they develop into tadpoles there. Other species, like the Túngara frog, lay their eggs in foam nests. Depending on the species, one or both adults make the nest by using their hind legs to whip up the eggs, water, and some mucus from their bodies until it turns into a frothy foam. The eggs hatch into tadpoles inside the foam. Depending on the species, the tadpoles may leave the nest and turn into froglets in the water, or they may stay inside and make the change inside the nest. The females of few species in this family, including the Puerto Rican coqui, mate and lay their eggs in plants that grow in trees. In the case of the Puerto Rican coqui, the male then takes charge of the nest, often sitting on top of them. These eggs skip the tadpole stage and hatch right into froglets. The golden coqui is the only member of the family to give birth to froglets. Instead of laying her eggs, the female keeps them inside her body, where they hatch into froglets. She then gives birth to the live young. The females in some species lay a few dozen eggs, but others can lay hundreds at a time. Usually the biggest frogs have the greatest number of eggs.

NOISE POLLUTION—FROM A FROG?

Until recently, no frogs lived in Hawaii. When the 2- to 2.5-inch-long frog, called the Puerto Rican coqui, hitchhiked to Hawaii in some plants, it found a good place to live and multiply. It started to do what it does naturally: After the sun sets, the males performed their two-part calls: koh-kee, koh-kee. People in Hawaii, however, were used to a quieter night, and some soon began complaining about the "racket" from the frogs, claiming that it disturbed their sleep and would possibly turn away island visitors. Despite their grumbles, the frog still lives in Hawaii and is doing well there.

LEPTODACTYLID FROGS AND PEOPLE

People hunt a few of the larger leptodactylid frogs for food and sometimes collect them and some of the pretty smaller species for the pet trade. Introduced coqui frogs have made the news in Hawaii. Hidden inside plants shipped to Hawaii from their native lands, coquis have found their new home to be a good place to live and raise families, but some people there are less pleased with the new arrivals. They complain about the male frogs' loud mating calls.

CONSERVATION STATUS

Of the 1,124 species in this family, the World Conservation Union (IUCN) lists two as Extinct, which means they are no longer in existence; 133 are Critically Endangered and facing an extremely high risk of extinction in the wild; 209 are Endangered and at very high risk of extinction in the wild; 133 are Vulnerable and facing a high risk of extinction in the wild; 60 are Near Threatened and at risk of becoming threatened with extinction in the future; and 249 are Data Deficient, which means not enough information is available to make a judgment about the threat of extinction.

SURINAM HORNED FROG (Ceratophrys cornuta): SPECIES ACCOUNTS

Physical characteristics: Also known as the horned frog, Amazonian horned frog, or packman frog, the Surinam horned frog is a large, fat-looking frog. Its round, rather flat body has the shape of a doughnut without the hole. Its wide head has an immense mouth that stretches from one side to the other, light tan eyes, and pointy eyebrows that resemble little horns. The body, which has small, scattered, cone-shaped warts across the back and down the sides, is green to yellowish green. Its back is patterned with brown, blotchy stripes, and a thin, brown band runs across the head from one eyebrow horn to the other. The frog usually sits with its rather small hind legs tucked up against the body and its short but thick front legs held pigeontoed, or facing inward. Both its front and hind legs are lime green with brown to dark green bands. The toes on the front feet are un-webbed, while those on the hind feet are partly webbed. The belly is smooth and cream-colored, and the throat is dark brown to black. Males and females look alike except during the mating season, when the males develop rough pads on the inner toe of each front foot. Adult females can grow to as much as 4.7 inches (12.0 centimeters) long from snout to rump. The males are smaller, reaching 3.1 inches (8.0 centimeters) in length.

Geographic range: The Surinam horned frog lives in the Amazon Basin, which is a large, low area of northern South America. In this region, heavy rains, small creeks, and streams all eventually drain into Amazon River. It also can be found in the small countries of French Guiana, Guyana, and Suriname.

Habitat: During most of the year, the horned frog stays on land and among the thick plants of the rainforest floor. In the breeding season, however, it moves into small pools of water, which may or may not dry up later in the season.

Diet: The Surinam horned frog is an opportunistic (ah-per-too-NIS-tik) hunter, which means that it will eat just about anything that it can grab and swallow. Prey includes grasshoppers and other insects, spiders, other frogs, and even quite large animals like snakes, lizards, and mice. The tadpoles, which have a long tooth-like poker on the bottom jaw, are also good hunters. They eat tadpoles, including other Surinam horned frog tadpoles, by opening their mouths and sucking them in. With a chomp of the jaws, the poker spears the prey, and the tadpole quickly swallows it.

Behavior and reproduction: Although it is a large frog, the Surinam horned frog can do quite a vanishing act. The ground of the rainforest is cluttered with growing plants and mounds of fallen leaves. This frog hops to such a mound, shuffles its body back and forth until all but its head is buried in the leaves, and then stops moving. With its pointy eyebrows that look like the edges of curled leaves and its camouflage colors, the frog nearly disappears. From here, it can watch for prey animals to walk unknowingly past. When one approaches closely enough, the frog lunges out, opens its immense mouth, and snaps it up. The frog may continue this style of sit-and-wait hunting, called ambush hunting, for several days from the same spot. It usually waits until dark on a rainy night to move to a new place.

Breeding season for this species is short, with all of the frogs mating and laying eggs when the first, heavy spring storms soak the land. The males hop to pools of water, sit on the edges, and make their deep calls. Some people describe the call as sounding like the "moo" of a cow or the "baa" of a sheep. When a female responds to a male's call, he climbs onto her back and hangs on by her front legs. The female lays up to 2,000 small eggs in the water. The eggs develop into tadpoles, which grow to about 2.5 inches (6.5 centimeters) long from head to tail before changing into froglets.

Surinam horned frogs and people: People see this frog more often in the pet store than in the wild.

Conservation status: The World Conservation Union (IUCN) does not consider this species to be at risk. Some of the areas where this frog lives are protected places, such as refuges and parks, but some are not. As more forests are logged and otherwise cleared, this frog's habitat is shrinking. ∎

BUDGETT'S FROG (Lepidobatrachus laevis): SPECIES ACCOUNTS

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 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. ∎

ROCK RIVER FROG (Thoropa miliaris): SPECIES ACCOUNTS

Physical characteristics: The Rock River frog has a typical frog shape: long hind legs with long toes, shorter front legs and toes, and a slender body and head with large, bulging eyes. The toes on its unwebbed front and back feet end in slightly widened tips. Eardrums show on each side of its rather wide head, just behind the rust-colored eyes. The frog is tan to reddish brown on its head, back, and legs, often with a noticeable dark stripe on each side of the body and running from almost the tip of the rounded snout to the start of the back leg. Its hind legs have dark brown to black bands. Its front legs have less banding. Its belly is gray, and it has a yellowish color at the tops of its hind legs. Males and females usually look alike, but in the breeding season, the males develop tiny spines on three of the front toes on each foot. Males are also slightly smaller than females. Females grow to 3.2 inches (8.1 centimeters) long from snout to rump, while males reach 2.8 inches (7.1 centimeters) in length.

Geographic range: It lives in a small area of southeastern Brazil near the Atlantic coast.

Habitat: It lives in warm and moist forests, especially along streams.

Diet: The Rock River frog probably eats arthropods, as do many of the other species in this family.

Behavior and reproduction: The Rock River frog becomes active at night, when it hops about on land looking for food. In the breeding season, the males climb onto streamside rocks and call. When females follow the calls to the males, they mate, and the females lay their eggs in the water. The eggs hatch into tadpoles, which use their long, strong tails to swim to the shoreline and up onto wet rocks.

Rock River frogs and people: People rarely see this species. It is not common in the pet trade.

Conservation status: The IUCN does not consider this species to be at risk, but it does live in areas where the habitat may disappear due to the cutting of trees and plants and the construction of buildings and dams. Scientists are also watching it to see whether a fungus that is killing off many different types of frogs worldwide may affect this species, too. ∎

PEREZ'S SNOUTED FROG (Edalorhina perezi): SPECIES ACCOUNTS

Physical characteristics: Perez's snouted frog has a dark brown to black stripe running along each side and separating its gray or brown back and head from its bright white underside. Its head has a rounded snout and two tan or gray and copper eyes are outlined on top with thin, finger-like bumps that look almost like long eyelashes. Its white belly has black markings, and its back has ridges that stretch from the back of the head to the rump. The back also sometimes has reddish brown stripes. Females are slightly larger than the males and grow to 1.4 inches (3.5 centimeters) long from snout to rump. The males reach 1.2 inches (3 centimeters) in length.

Geographic range: It lives in the Amazon River basin from southern Colombia to northern Bolivia.

Habitat: Perez's snouted frog lives in valleys and other low-lying areas of the wet and warm tropical rainforests. They breed in small pools of water, usually those that dry up later in the year.

Diet: The adult diet includes flies, crickets, and other insects, as well as spiders and other arthropods.

Behavior and reproduction: During the daytime, this frog hops through the piles of leaves on the rainforest floor and looks for things to eat. It relies on the dead-leaf colors of its head and back to hide it from the scanning eyes of predators. In the breeding season, each of the males begins to call from his spot in the leaves. When a female approaches, the male climbs on her back and hangs on near her front legs as they scuttle off to a pool of water. There, the female lays 78 to 98 eggs. The male and female together beat the water, eggs, and fluid from their bodies into foam, which floats on top of the water. In four to six days, the eggs hatch into tadpoles, which swim out of the foam nest into the water. The tadpoles have tan backs and greenish yellow bellies and can grow to about 0.8 inches (2 centimeters) before turning into froglets.

Perez's snouted frogs and people: People rarely see this species. It is not common in the pet trade.

Conservation status: The IUCN does not consider this common species to be at risk. While some of its habitat is disappearing as people move into the area or turn the forests into farmland, these frogs seem to be doing very well in the wild. ∎

SOUTH AMERICAN BULLFROG (Leptodactylus pentadactylus): SPECIES ACCOUNTS

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 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. ∎

GOLD-STRIPED FROG (Lithodytes lineatus): SPECIES ACCOUNTS

Physical characteristics: True to its name, the gold-striped frog has two golden yellow stripes, each one running from its rounded snout above the brown eye and eardrum and down its slender, slightly warty back to the rump. Its legs are tan with black bands, often faded on the front legs, and end in unwebbed toes that are tipped with small pads. Small red blotches show at the top of the hind legs. The frog's smooth underside is light grayish brown. Males and females look alike, although the females are slightly larger. Females can reach 2.2 inches (5.6 centimeters) long from snout to rump, while males grow to 1.8 inches (4.5 centimeters) in length.

Geographic range: This frog is found in the Amazon River basin of northern South America, as well as in the Guianas.

Habitat: For most of the year, gold-striped frogs are found in hot, moist, low-lying rainforests.

Diet: Adults search the forest floor for earthworms and arthropods to eat.

Behavior and reproduction: Although young gold-striped frogs may hop about on land in the daytime and at night, the adults usually go out only after dark. In the daylight, the adults hide from sight in underground burrows, sometimes inside the nests of leaf-cutting ants. During breeding times, the males call from their daytime getaways. When a female approaches the male, he hops onto her back, and they head for water. She lays about 200 eggs inside a foam nest that they make near the edge of the water. The eggs hatch into tadpoles, which stay inside the nest for about one to two weeks, and then swim off into the water. In about nine weeks, when the bright pink tadpoles are as much as 2 inches (5 centimeters) long, they turn into froglets.

Gold-striped frogs and people: People often mistake this species for a poison dart frog. While poison dart frogs ooze what can be dangerous poison from their skin, the gold-striped frogs do not.

Conservation status: This common species is not considered endangered or threatened. ∎

GRAY FOUR-EYED FROG (Pleurodema bufonina): SPECIES ACCOUNTS

Physical characteristics: The gray four-eyed frog gets its name from the two, large, dark-colored glands on its hips. When looking at the frog from the back end, the glands look somewhat like oval-shaped eyes. This species has a short, rounded snout, small eardrums, short and chubby front legs that have unwebbed toes, and longer hind legs with slightly webbed toes. Its upper body is brown, sometimes with darker brown spots and often with a thin, light stripe down the middle of the back. Its underside is light tan. Males and females look alike, but females are a bit larger. Females grow to 2.2 inches (5.6 centimeters) from snout to rump, while males can reach 1.8 inches (4.5 centimeters) in length.

Geographic range: This frog lives farther south than any other frog in the world. It makes its home in Chile and nearby parts of western Argentina, including the area around the Straits of Magellan near the southern tip of South America.

Habitat: Gray four-eyed frogs may live anywhere from the lowlands to mountain sites as high as 7,500 feet (2,300 meters) above sea level. Its home is in grasslands and scrubby areas, often alongside lakes.

Diet: Although they do not know for sure, scientists think these frogs eat small arthropods.

Behavior and reproduction: Unlike many other frogs in this family, which are active mainly at night, adult gray four-eyed frogs may hop about on land both during the day and at night. They are especially active during wet weather and tend to move under stones or into cracks in or between rocks during drier spells. During the spring breeding season, males and females meet in shallow water along lakeshores. The males do not call. To mate, a male climbs onto a female's back and holds on near her hind legs. In the water, she lays a string of eggs, which hatch into grayish brown tadpoles. The tadpoles grow to as much as 1.4 inches (3.5 centimeters) long before changing into froglets.

Gray four-eyed frogs and people: People do not hunt this frog. It is not popular in the pet trade.

Conservation status: The IUCN does not consider this very common species to be endangered or threatened. ∎

PATAGONIA FROG (Atelognathus patagonicus): SPECIES ACCOUNTS

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 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. ∎

FOR MORE INFORMATION

Books:

Cogger, Harold G., and Richard G. Zweifel. Encyclopedia of Reptiles and Amphibians. San Diego, CA: Academic Press, 1998.

Halliday, Tim, and Kraig Adler, eds. The Encyclopedia of Reptiles and Amphibians (Smithsonian Handbooks). New York: Facts on File, 1991.

Mattison, Chris. Frogs and Toads of the World. New York: Facts on File Publications, 1987.

Patent, Dorothy Hinshaw. Frogs, Toads, Salamanders, and How They Reproduce. New York: Holiday House, 1975.

Ryan, Michael J. The Túngara Frog. Chicago: University of Chicago Press, 1985.

Showler, Dave. Frogs and Toads: A Golden Guide. New York: St. Martin's Press, 2004.

Stebbins, Robert C. A Field Guide to Western Reptiles and Amphibians (Peterson Field Guide Series). Boston: Houghton Mifflin, 1966.

Periodicals:

Raloff, Janet. "Hawaii's Hated Frogs: Tiny Invaders Raise a Big Ruckus." Science News, January 4, 2003 (vol. 163): 11.

Web sites:

"Amphibians - Leptodactylidae: Tropical Frogs." Project Amazonas Inc.http://www.projectamazonas.com/subpages/floraandfauna/FloraFaunaGalleries/amphibians-tropical%20frogs%20gallery.htm (accessed on March 1, 2005).

"Atelognathus patagonicus." CalPhotos. http://elib.cs.berkeley.edu/cgi/img_query?query_src=aw_lists_genera_&elarge=1111+1111+111+2039 (accessed on March 1, 2005).

"Big Bark, Big Bite." American Museum of Natural History.http://www.amnh.org/exhibitions/frogs/featured/bigbark.php (accessed on March 1, 2005).

"Ceratophrys cornuta." Amphibians.http://www.rieo.net/amph/exfrog/tuno/cerato/amazon.htm (accessed on March 1, 2005).

"Family Leptodactylidae (Neotropical Frogs)." Animal Diversity Web.http://animaldiversity.ummz.umich.edu/site/accounts/pictures/Leptodactylidae.html (accessed on March 1, 2005).

"Frog Legs." American Museum of Natural History.http://www.amnh.org/exhibitions/frogs/featured/froglegs.php (accessed on March 1, 2005).

"Lepidobatrachus laevis." Amphibians.http://www.rieo.net/amph/exfrog/tuno/lepido/laevis.htm (accessed on March 1, 2005).

"Pleurodema bufonina." CalPhotos. http://elib.cs.berkeley.edu/cgi/img_query?stat=BROWSE_IMG&query_src=photos_browseimgs_amphibian_sci&where-lifeform=Amphibian&where-taxon=Pleurodema+bufonina+(female) (accessed on March 1, 2005).

"Smokey Jungle Frog." Wildherps.com.http://www.wildherps.com/species/L.pentadactylus.html (accessed on March 1, 2005).