Rio Grande leopard frogs are gray, green, or brown on their back with dark brown spots. The spots are olive green or light tan on the edge. They have pale yellow lines or folds of skin running down their back. Their belly is cream colored, turning into pale yellow on the tops of the legs. Adults have an pointed noses and long, powerful legs. Rio Grande leopard frogs are 5.7 to 11.4 cm long. (Dubois, 2003; Hillis, 1982; Robinson, 2004; Sanders, 1973)
Adult males have noticeable flaps of skin under their mouth, and females have smaller ones. Females are usually lighter in color and smaller. Tadpoles are olive green with a pale yellow tint on their sides and back. Their eyes are golden with tiny black specks. The tails have pale and dark spots, and the nose is more rounded than it is in adults. (Dubois, 2003; Hillis, 1982; Robinson, 2004; Sanders, 1973)
Rio Grande leopard frogs live from central and western Texas through New Mexico and farther south to Veracruz, Mexico. They Some scientists say that frogs that look like this south of Veracruz, Mexico, are actually Mexican leopard frogs. (Hammerson, et al., 2003; Robinson, 2004; Stebbins, 1966)
Rio Grande leopard frogs live in streams that run during all or part of the year. They live along streams and rivers, in springs, ponds of farmed fish, standing water, and water kept for animals or used for farming. They live in grasslands, shrub habitats, savanna, deserts, and grasslands with trees. They can live in dry or cold places, but are usually not far from water. They are active all year, except when it's really cold outside. They live at elevations up to 701.4 m and as far as .9 m underground. (Robinson, 2004; Sterner, 2005; Texas Memorial Museum, 2006)
Rio Grande leopard frogs breed in the water. After a few days, the eggs become tiny tadpoles that are surrounded by see-through jelly. A few weeks later, the tadpoles hatch and break out of the layers. When they hatch, their head and body are visible and they have a shrunken tail. Once they become unstuck from the the jelly, they eat algae. After 6 weeks, the sides of their heads swell and turn into gills that they breathe through. Later, the gills move inside their bodies and are covered by a skin flap. The tail shrinks and they transform into toads. Their gills turn in to lungs. The transformation takes 3 months. Rio Grande leopard frogs grow until they are 3 years old, and then they can have their own offspring. (Hickman, et al., 2009; Punzo, 2005)
In warmer places like Mexico, Rio Grande leopard frogs mate any time during the year. In the United States, they mostly breed in the spring and fall. As it gets warmer, males call to females with special mating trills that can be heard from up to 1 mile away. Competing nearby males may make a chuckle call to confuse females. After a male has established a territory, he fends off rival males by getting on top of them and pushing their head toward the ground. The second male accepts by leaving his head on the ground. (Gambs and Littlejohn, 1979; Hickman, et al., 2009; Punzo, 2005)
Both males and females have multiple mates. Females let their eggs go into the water, but this can can be interrupted by a competing male. (Gambs and Littlejohn, 1979; Hickman, et al., 2009; Punzo, 2005)
Great Basin leopard frogs breed in the spring and summer when it rains a lot. In warmer places, they breed year-round. Scientists aren't sure exactly how many eggs they lay, but other leopard frogs can lay hundreds to thousands of eggs. Females lay eggs in water that's pretty still, and they hatch into tadpoles in 3 weeks. The tadpoles float down the river with the the current, but most of them are eaten before they become adults. Juveniles that survive are able to breed after 2 to 3.5 years. (Gambs and Littlejohn, 1979; Punzo, 2005; Sterner, 2005)
Rio Grande leopard frogs lay eggs on top of plants in a quiet spot in the water. Besides that, parents don't invest time or energy into the young. (Gambs and Littlejohn, 1979; Parker and Goldstein, 2004)
Rio Grande leopard frogs are usually found alone, but gather together when they are breeding. Males are territorial during the breeding season. They make chuckle calls as a response to other males. Like many frogs that live in stream, they are almost always close to the water. Males exhibit territorial behavior at this time, and may give "chuckle" calls in response to the calls of other males. Typical of stream frogs, they are seldom found far from water. Rio Grande leopard frogs are mostly active at night. Farther north, they hibernate in the winter when it's very cold. (Dubois, 2003; Hickman, et al., 2009; Robinson, 2004; Texas Memorial Museum, 2006)
Rio Grande leopard frogs call to each other during mating or to tell others that there are predators nearby. The names of the calls that males make are distress calls, release calls, mating trills and chuckle calls. Release calls are made by males when another male is on top of them. Males make advertisement calls, which are also called mating trills, to announce themselves to females. They also announce their specific spot to other males. Males make chuckle calls in response to the advertisement calls of other males, as a way to defend their territory. Females make a distress call if they are threatened by a predator, but it's not as loud as the call of males. Rio Grande leopard frogs use sight, hearing, touch, and chemicals to understand their environment. Like other frogs, they have excellent hearing, and are especially good at understanding calls of their own species. (Conant, 1975; Gambs and Littlejohn, 1979; Hickman, et al., 2009; Robinson, 2004)
Rio Grande leopard frogs eat different kinds of other animals, depending on what is available. In the spring they eat sawflies, wasps, bees and ants, moths and butterflies, and beetles. In the fall, they eat equal amounts of these insects, dragonflies and damselflies, bugs, and grasshoppers, crickets, weta, and locusts. Rio Grande leopard frogs hunt at night. Their tadpoles eat algae and some phytoplankton. (Dubois, 2003; Parker and Goldstein, 2004)
Rio Grande leopard frogs have camouflage coloring, which helps them avoid predators. They hide under rocks and in plants along streams in the day. If they are living around predatory fish, they find cover in plants. Rio Grande leopard frog tadpoles stay away from predators by swimming in quick bursts. (Dubois, 2003; Texas Memorial Museum, 2006)
Rio Grande leopard frogs are a food source for crayfish, turtles, fishes, birds and small mammals. They get parasites like mites and roundworms in their liver. They can also get the deadly chytrid fungus. Finally, some scientists think that since they were introduced, they caused a decrese in the number of native lowland leopard frogs in southeastern California. (Conant, 1975; Dubois, 2003; Gambs and Littlejohn, 1979; Robinson, 2004; Rorabaugh, et al., 2002)
Rio Grande leopard frogs are not endangered, but they live in protected areas and are listed as "Special Protection" in the Red Data book of the Mexican government. They actually threaten native frogs when they spread, so there are strategies to stop them from spreading rather than protect them. (Hammerson, et al., 2003)
The scientific name of Rio Grande leopard frogs was changed to Lithobates berlandieri, though many scientists still use their old name. Rio Grande leopard frogs have had a few different names, and at one point were a subspecies of Northern leopard frogs. (Gambs and Littlejohn, 1979; Hammerson, et al., 2003)
Kinsey Brock (author), University of Michigan-Ann Arbor, Phil Myers (editor), University of Michigan-Ann Arbor, Rachelle Sterling (editor), Special Projects, Catherine Kent (editor), Special Projects.
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