Lithobates berlandieriRio Grande Leopard Frog

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Geographic Range

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. (Hammerson, et al., 2003; Robinson, 2004; Stebbins, 1966)

Habitat

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. (Robinson, 2004; Sterner, 2005; Texas Memorial Museum, 2006)

  • Aquatic Biomes
  • lakes and ponds
  • rivers and streams
  • temporary pools
  • Range elevation
    0 to 701.4 m
    0.00 to 2301.18 ft
  • Average depth
    .9 m
    2.95 ft

Physical Description

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. (Dubois, 2003; Hillis, 1982; Robinson, 2004; Sanders, 1973)

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. (Dubois, 2003; Hillis, 1982; Robinson, 2004; Sanders, 1973)

  • Sexual Dimorphism
  • male larger
  • sexes colored or patterned differently
  • male more colorful
  • sexes shaped differently
  • Range length
    5.7 to 11.4 cm
    2.24 to 4.49 in

Development

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. (Hickman, et al., 2009; Punzo, 2005)

Reproduction

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. (Gambs and Littlejohn, 1979; Hickman, et al., 2009; Punzo, 2005)

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. (Gambs and Littlejohn, 1979; Hickman, et al., 2009; Punzo, 2005)

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. (Gambs and Littlejohn, 1979; Hickman, et al., 2009; Punzo, 2005)

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. (Gambs and Littlejohn, 1979; Punzo, 2005; Sterner, 2005)

  • 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

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. (Gambs and Littlejohn, 1979; Parker and Goldstein, 2004)

  • Parental Investment
  • no parental involvement
  • pre-fertilization
    • provisioning
    • protecting
      • female

Lifespan/Longevity

The lifespan of Rio Grande leopard frogs is unknown. (Hickman, et al., 2009; Robinson, 2004)

Behavior

Rio Grande leopard frogs are solitary animals, but gather together during breeding periods. 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. These frogs can be active during the day, but are most likely to be found active at night. They hibernate during winter in colder habitats, but southern populations may remain active year-round. (Dubois, 2003; Hickman, et al., 2009; Robinson, 2004; Texas Memorial Museum, 2006)

Home Range

The territory size for Rio Grande leopard frogs is unknown. (Conant, 1975; Robinson, 2004; Texas Memorial Museum, 2006)

Communication and Perception

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. (Conant, 1975; Gambs and Littlejohn, 1979; Hickman, et al., 2009; Robinson, 2004)

Food Habits

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. (Dubois, 2003; Parker and Goldstein, 2004)

  • Animal Foods
  • amphibians
  • insects
  • terrestrial non-insect arthropods

Predation

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. (Dubois, 2003; Texas Memorial Museum, 2006)

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. (Dubois, 2003; Texas Memorial Museum, 2006)

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. (Dubois, 2003; Texas Memorial Museum, 2006)

  • Anti-predator Adaptations
  • cryptic

Ecosystem Roles

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. (Conant, 1975; Dubois, 2003; Gambs and Littlejohn, 1979; Robinson, 2004; Rorabaugh, et al., 2002)

Commensal/Parasitic Species
  • mites (Hannemania hylae)
  • liver parasites (Mesocestoides)
  • chytrid fungus (Batrachochytrium dendrobatidis)

Economic Importance for Humans: Positive

Rio Grande leopard frogs are not known to provide economic benefits to humans. (Dubois, 2003; Frost, et al., 2006; Hillis, 1982; Texas Memorial Museum, 2006)

Economic Importance for Humans: Negative

There are no known adverse effects of Rio Grande leopard frogs on humans. (Robinson, 2004; Texas Memorial Museum, 2006)

Conservation Status

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. (Hammerson, et al., 2003)

Other Comments

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. (Frost, et al., 2006; Gambs and Littlejohn, 1979; Stebbins, 1966)

Contributors

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.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

Neotropical

living in the southern part of the New World. In other words, Central and South America.

World Map

acoustic

uses sound to communicate

agricultural

living in landscapes dominated by human agriculture.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

choruses

to jointly display, usually with sounds, at the same time as two or more other individuals of the same or different species

cryptic

having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.

desert or dunes

in deserts low (less than 30 cm per year) and unpredictable rainfall results in landscapes dominated by plants and animals adapted to aridity. Vegetation is typically sparse, though spectacular blooms may occur following rain. Deserts can be cold or warm and daily temperates typically fluctuate. In dune areas vegetation is also sparse and conditions are dry. This is because sand does not hold water well so little is available to plants. In dunes near seas and oceans this is compounded by the influence of salt in the air and soil. Salt limits the ability of plants to take up water through their roots.

ectothermic

animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature

external fertilization

fertilization takes place outside the female's body

fertilization

union of egg and spermatozoan

freshwater

mainly lives in water that is not salty.

heterothermic

having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.

hibernation

the state that some animals enter during winter in which normal physiological processes are significantly reduced, thus lowering the animal's energy requirements. The act or condition of passing winter in a torpid or resting state, typically involving the abandonment of homoiothermy in mammals.

insectivore

An animal that eats mainly insects or spiders.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

marsh

marshes are wetland areas often dominated by grasses and reeds.

metamorphosis

A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nocturnal

active during the night

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

phytoplankton

photosynthetic or plant constituent of plankton; mainly unicellular algae. (Compare to zooplankton.)

polygynandrous

the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.

riparian

Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).

saltatorial

specialized for leaping or bounding locomotion; jumps or hops.

scrub forest

scrub forests develop in areas that experience dry seasons.

seasonal breeding

breeding is confined to a particular season

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

solitary

lives alone

suburban

living in residential areas on the outskirts of large cities or towns.

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

visual

uses sight to communicate

year-round breeding

breeding takes place throughout the year

References

Conant, R. 1975. A Field Guide to Reptiles and Amphibians. Boston: Houghton Mifflin Company.

Dubois, A. 2003. True Frogs. Pp. 245-264 in W Duellman, ed. Grzimek's Animal Life Encyclopedia, Vol. Vol. 6, 2nd Edition. Farmington Hills, MI: Gale Group, Inc..

Frost, D., T. Grant, J. Faivovich, R. Bain, A. Haas. 2006. The Amphibian Tree of Life. Bulletin of the American Museum of Natural History, Vol. 297: 370.

Gambs, R., M. Littlejohn. 1979. Acoustic Behavior of Males of the Rio Grande Leopard Frog (Rana berlandieri): An Experimental Analysis Through Field Playback Trials. Copeia, Vol. 1979 / No. 4: 643-650.

Hammerson, G., G. Köhler, L. Wilson. 2003. "Lithobates berlandieri (Rio Grande Leopard Frog)" (On-line). Accessed March 11, 2010 at www.iucnredlist.org/apps/redlist/details/58561/0.

Hickman, C., L. Roberts, S. Keen, A. Larson, D. Eisenhour. 2009. Animal Diversity. New York, NY: McGraw-Hill Companies.

Hillis, D. 1982. Morphological Differentiation and Adaptation of the Larvae of Rana berlandieri and Rana sphenocephala in Sympatry. American Society of Ichthyologists and Herpetologists, Vol. 1: 168-174.

Parker, M., M. Goldstein. 2004. Diet of the Rio Grande Leopard Frog (Rana berlandieri). Journal of Herpetology, Vol. 38 / No. 1: 127-130.

Punzo, F. 2005. Effects of Insecticide Exposure on Activity and Swimming Performance of Tadpoles of the Rio Grande Leopard Frog. The Texas Journal of Science, Vol. 57/ No. 3: 264-271.

Robinson, A. 2004. "Rana berlandieri" (On-line). AmphibiaWeb. Accessed March 20, 2010 at http://amphibiaweb.org/cgi/amphib_query?where-genus=Rana&where-species=berlandieri&account=amphibiaweb.

Rorabaugh, J., M. Sredl, V. Miera, C. Drost. 2002. Continued Invasion by an Introduced Frog. The Southwestern Naturalist, Vol. 47 / 1: 12-20.

Sanders, O. 1973. A New Leopard Frog from Southern Mexico. Journal of Herpetology, Vol. 7 / 2: 87-92.

Stebbins, R. 1966. A Field Guide to Western Reptiles and Amphibians. Boston: Houghton Mifflin Company.

Sterner, R. 2005. "Elevation Map of United States" (On-line). Accessed March 20, 2010 at http://birell.org/andrew/reliefMaps/.

Texas Memorial Museum, 2006. "Herps of Texas" (On-line). Accessed March 20, 2010 at http://www.zo.utexas.edu/research/txherps/frogs/rana.berlandieri.html.