Chiefly a stream dweller, this species of frog utilizes both temporary and permanent water. Lithobates berlandieri has been found along streams and rivers, springs, stock ponds, backwaters, cattle tanks, canals, drainage ditches, arroyo pools in grassland, shrubland, savanna, desert, and woodland areas. Rio Grande leopard frogs are seldom found far from water, but can tolerate fairly dry or cold conditions by burrowing. This species is active all year round except in periods of low temperature. They are found at elevations of up to 701.4 meters and depths of .9 meters.
Range elevation: 0 to 701.4 m.
Average depth: .9 m.
Habitat Regions: temperate ; tropical ; terrestrial ; freshwater
Terrestrial Biomes: desert or dune ; savanna or grassland ; scrub forest
Aquatic Biomes: lakes and ponds; rivers and streams; temporary pools
Wetlands: marsh
Other Habitat Features: suburban ; agricultural ; riparian
Checkered garter snakes, painted turtles, and great-tailed grackles have been observed eating adult and tadpole Lithobates berlandieri. These frogs are also prey to crayfish, birds, turtles, fish, small mammals and humans.
Rio Grande leopard frogs are cryptically colored with earth tones and blends in with its surroundings. This frog species seeks shelter under rocks and in streamside vegetation during the day. Where they are found in the same environment as predatory fishes, they use dense aquatic vegetation for cover. Tadpoles of this species avoid predators by burst swimming.
Rio Grande leopard frogs are eaten by crayfish, birds, turtles, fish, small mammals and humans. Researchers have reported them being eaten by checkered garter snakes, painted turtles, and great-tailed grackles.
Known Predators:
Anti-predator Adaptations: cryptic
Rio Grande leopard frogs are 5.7 to 11.4 cm long from snout to vent. The dorsal surface varies from gray to green to brown in color and is covered by many irregular dark brown spots. These spots have olive green and light tan color around their edges. Prominent dorsolateral folds turn inward in front of the groin, and are usually pale yellow in color. Mottling of color is common on the chin of older individuals. The ventral surface is most often cream colored fading into a pale yellow around the upper thighs. Adults have an angular nose and long powerful legs.
Adult males posses well developed external vocal sacs, while females tend to have smaller, less obvious vocal sacs. Another sexual dimorphism is the conspicuous vestigial oviducts present on adult males. Adult females are often lighter in color, smaller in size, and overall less conspicuous than males. Tadpoles of this species are olive with a pale yellow cast on the sides and dorsum. The irises are gold and contain tiny flecks of black. The tail is marked with pale and dark spots, and the snout is more rounded than in adults.
Range length: 5.7 to 11.4 cm.
Other Physical Features: ectothermic ; heterothermic ; bilateral symmetry
Sexual Dimorphism: male larger; sexes colored or patterned differently; male more colorful; sexes shaped differently
The lifespan of Rio Grande leopard frogs is unknown.
Lithobates berlandieri has been renamed Lithobates berlandieri, but the nomenclature is not yet standard. This species has been known by several scientific names, most notably as a subspecies of Lithobates pipiens.
Lithobates berlandieri is found mostly in the Nearctic range; from Central Texas through New Mexico and farther south into Veracruz, Mexico, where it overlaps slightly into the Neotropical range. More specifically, the species occurs in the United States from central and western Texas to the Pecos River drainage in Eddy County, southeastern New Mexico. In Mexico this frog is found south along the Atlantic slope through at least southeastern Mexico. Some consider the southern limit of the distribution to be near Veracruz, Mexico, and suggest that frogs of similar appearance found farther south are a different species, Lithobates brownorum.
Biogeographic Regions: nearctic (Native ); neotropical (Native )
The diverse adult diet is reflective of a generalist opportunistic predator. Dietary shifts between seasons are necessary for the survival of this species. Rio Grande leopard frogs' spring diets include invertebrates of the genera Hymenoptera, Lepidoptera, and Coleoptera. A more diverse diet, which includes equal percentages of Odonata, Coleoptera, Hymenoptera, Hemiptera, and Orthoptera is consumed in the fall months. This species is nocturnal and hunts at night. The tadpoles of Lithobates berlandieri feed on algae, inorganic particles, and diatoms.
Animal Foods: amphibians; insects; terrestrial non-insect arthropods
Plant Foods: algae; phytoplankton
Primary Diet: carnivore (Insectivore )
Rio Grande leopard frogs are a food source for crayfish, turtles, fishes, birds and small mammals. It also serves as a host for several species of mites and nematodes including Hannemania hylae and species of the genus Mesocestoides. Lithobates berlandieri can also contract the deadly chytrid fungus. Some scientists speculate that the introduction of Lithobates berlandieri has been responsible for the decline of the native lowland leopard frogs (Lithobates yavapaiensis) in southeastern California.
Commensal/Parasitic Species:
Rio Grande leopard frogs are not known to provide economic benefits to humans.
There are no known adverse effects of Rio Grande leopard frogs on humans.
Reproduction in Rio Grande leopard frogs is aquatic. The eggs are fertilized externally and remain in queit, shallow water attached to emerged vegetation. The eggs develop immediately, and within a few days the embryos develop into tiny tadpoles surrounded by translucent jelly layers. After a few weeks, the embryonic tadpoles hatch from their eggs to become free living. At hatching, tadpoles have a distinct head and body with a compressed tail. Once free of the nourishing yolk sac, tadpoles feed on algae and diatoms to support their development. About 6 weeks into development swelling occurs on each side of the head, and these later become external gills. These gills later transform into internal gills that are eventually covered with an operculum. The hindlimbs appear first, as the forelimbs are hidden by the operculum in this stage. The tail is absorbed, and the mouth undergoes a transformation into the adult condition. Lungs develop, and the gills are absorbed. This whole process is usually completed within 3 months. Rio Grande leopard frogs will continue to grow until about 3 years of age when they reach sexual maturity.
Development - Life Cycle: metamorphosis
Lithobates berlandieri is not a species of concern for any of the United States. However, the IUCN Red List states this species occurs in several protected areas and it is listed under Special Protection in the Red Data book of the Mexican Government. The spread of this species into non-native regions threatens native frog populations, thus management strategies have been suggested to prevent the spread of them.
US Federal List: no special status
CITES: no special status
IUCN Red List of Threatened Species: least concern
Rio Grande leopard frogs produce two types of calls to communicate during mating, or times of distress. For males, there are four main categories of acoustic repertoire: distress calls, release calls, mating trills and chuckle calls. A release call is only emitted by a male when he is mounted by another male. Advertisement calls, or mating trills, are emitted by males and used by females in order to identify conspecific mates. These calls are also used by males to announce occupied space to other males. Chuckle calls are emitted by males upon hearing the advertisement call of another male. The chuckle call serves as a territorial signal to an intruding male. Females of this species can produce a distress call when threatened by a predator, however the call is not as loud as that of the male. Rio Grande leopard frogs perceive their environment through visual, auditory, tactile, and chemical stimuli. Like most frogs, they perceive the calls of its own kind with an acute sense of hearing.
Communication Channels: visual ; acoustic
Other Communication Modes: choruses
Perception Channels: visual ; tactile ; acoustic ; chemical
In warm climates such as Mexico, Rio Grande leopard frogs are able to mate all year round. In the United States, breeding peaks in the spring and fall. As weather warms, males call to females using their loudest repertoire of mating trills, which can often be heard from up to a mile away. Upon hearing the mating trill of a male, a nearby competitor may emit a chuckle call to confuse potential females. Once a male has established a territory, he wards off rival males by mounting them and pushing their head to the ground. If a mounted male can not fight back, he submits to his competitor by leaving his head on the ground.
Rio Grande leopard frogs are polygynandrous, that is, males and females engage in several brief courtships during a breeding period. Once a female chooses a suitable male, the couple enters the water to release their eggs and sperm. However, this process can be interrupted by a nearby smaller male, who will also attach himself to the female before the established couple can enter the water. It is not uncommon for a female to be crushed in this process.
A female enters the water and is immediately clasped by the male in a process called amplexus, during which eggs are fertilized externally. As the female lays eggs, the male discharges his sperm over the eggs to fertilize them. After laying the fertilized eggs on vegetation in a location of limited disturbance, the male and female part ways in hopes of finding another mate. Parental care is therefore very minimal.
Mating System: polygynandrous (promiscuous)
Great Basin leopard frogs usually breed when rainfall is plentiful, generally spring and summer months. In some populations that inhabit warmer climates, this species may breed year round. Exact clutch size is unknown for this species, but closely related leopard frogs are known to lay hundreds to thousands of eggs. Females lay eggs in quiet water on submerged vegetation, and these hatch into tadpoles within 3 weeks. Tadpoles are adapted to life in streams and are often transported passively downstream. Most tadpoles are preyed upon by stream dwellers and do not survive to adulthood. Juveniles that do survive will reach reproductive maturity at 2 to 3.5 years of age.
Breeding interval: Rio Grande leopard frogs may breed all year round with warm temperatures and sufficient rainfall.
Breeding season: Rio Grande leopard frogs can reproduce all year round, but most often reproduce in the spring and fall.
Range time to hatching: 1.5 to 3 weeks.
Range age at sexual or reproductive maturity (female): 2 to 3.5 years.
Average age at sexual or reproductive maturity (female): 3 years.
Range age at sexual or reproductive maturity (male): 2 to 3.5 years.
Average age at sexual or reproductive maturity (male): 3 years years.
Key Reproductive Features: iteroparous ; seasonal breeding ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (External ); oviparous
There is no parental investment in Rio Grande leopard frogs beyond laying fertilized eggs on vegetation in a safe, undisturbed aquatic habitat. Courtship and fertilization is brief, and males and females part ways immediately afterward.
Parental Investment: no parental involvement; pre-fertilization (Provisioning, Protecting: Female)
The Rio Grande leopard frog (Lithobates berlandieri or Rana berlandieri)[2][3] is a species of aquatic frog native to the southern United States in Texas and New Mexico, and south through Mexico and Central America.[1] It is also sometimes referred to as the Mexican leopard frog. The epithet berlandieri is in honor of the naturalist Jean Louis Berlandier, who worked for the Mexican government on one of the first biological surveys of Texas.[4][5]
Rio Grande leopard frogs grow from 2.2 to 4.5 inches (5.6 to 11.4 cm) in length. They are usually tan, brown, or pale green in color, with distinctive black spotting with prominent light-colored ridges down either side of their backs. Their noses are angular, and they have long, powerful legs with webbed feet.
The species is primarily aquatic, and mostly nocturnal, though they can be often found during the day resting along the edge of the water. Despite their geographic range being mostly arid or semiarid, they inhabit permanent water sources, such as streams, creeks, and ponds. They are insectivorous, but like most frogs, will eat almost anything they can overpower and swallow. Mating occurs during the rainy periods of the spring and fall. The males make a rattling call which is loud enough to be heard a quarter mile or more away. Eggs are laid in large masses attached to aquatic vegetation.
The Rio Grande leopard frog was once considered a subspecies of the northern leopard frog, but was later recognized as a distinct species due to distinct mating call and morphological differences. Recent research has placed Rio Grande leopard frogs in the Scurrilirana species group[2][6] of the subgenus Pantherana.[3]
Found from Central Texas to New Mexico (where it is listed as vulnerable), south to Mexico through the Yucatán Peninsula, Belize, Guatemala, and Honduras to northeastern Nicaragua,[1] its presence uncertain in El Salvador.[1]
It is easily confused with other species that share its range, such as the Plains leopard frog (Lithobates blairi). It is unknown whether hybridization occurs. The species has also been introduced to the Colorado River in California and Arizona, and is known to be expanding its range south into Mexico in the state of Baja California. It is believed to be contributing to the population reduction of the lowland leopard frog (Lithobates yavapaiensis), which is native to the region. This expansion of range is the primary factor in the Rio Grande leopard frog being classified as least concern, by the IUCN Red List.
The Rio Grande leopard frog (Lithobates berlandieri or Rana berlandieri) is a species of aquatic frog native to the southern United States in Texas and New Mexico, and south through Mexico and Central America. It is also sometimes referred to as the Mexican leopard frog. The epithet berlandieri is in honor of the naturalist Jean Louis Berlandier, who worked for the Mexican government on one of the first biological surveys of Texas.