Geographic Range
Rana 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,
Rana brownorum
.
- Biogeographic Regions
- nearctic
- neotropical
Habitat
Chiefly a stream dweller, this species of frog utilizes both temporary and permanent
water.
Rana 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.
- 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
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.
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.
- Other Physical Features
- ectothermic
- heterothermic
- bilateral symmetry
- Sexual Dimorphism
- male larger
- sexes colored or patterned differently
- male more colorful
- sexes shaped differently
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.
- Development - Life Cycle
- metamorphosis
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.
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.
- Key Reproductive Features
- iteroparous
- seasonal breeding
- year-round breeding
- gonochoric/gonochoristic/dioecious (sexes separate)
- sexual
- fertilization
- 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
Lifespan/Longevity
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.
- Key Behaviors
- terricolous
- saltatorial
- nocturnal
- motile
- hibernation
- solitary
- territorial
Home Range
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.
- Other Communication Modes
- choruses
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
Rana berlandieri
feed on algae, inorganic particles, and
diatoms
.
- Primary Diet
- carnivore
- Animal Foods
- amphibians
- insects
- terrestrial non-insect arthropods
- Plant Foods
- algae
- phytoplankton
Predation
Checkered garter snakes
,
painted turtles
, and
great-tailed grackles
have been observed eating adult and tadpole
Rana 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
.
- 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
.
Rana berlandieri
can also contract the deadly
chytrid fungus
. Some scientists speculate that the introduction of
Rana berlandieri
has been responsible for the decline of the native lowland leopard frogs (
Rana yavapaiensis
) in southeastern California.
- 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.
Economic Importance for Humans: Negative
There are no known adverse effects of Rio Grande leopard frogs on humans.
Conservation Status
Rana 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.
Other Comments
Rana 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
Rana pipiens
.
Additional Links
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.
- 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.
- native range
-
the area in which the animal is naturally found, the region in which it is endemic.
- Neotropical
-
living in the southern part of the New World. In other words, Central and South America.
- native range
-
the area in which the animal is naturally found, the region in which it is endemic.
- 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).
- tropical
-
the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.
- terrestrial
-
Living on the ground.
- freshwater
-
mainly lives in water that is not salty.
- 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.
- 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.
- scrub forest
-
scrub forests develop in areas that experience dry seasons.
- marsh
-
marshes are wetland areas often dominated by grasses and reeds.
- suburban
-
living in residential areas on the outskirts of large cities or towns.
- agricultural
-
living in landscapes dominated by human agriculture.
- riparian
-
Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).
- ectothermic
-
animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature
- 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.
- 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.
- polygynandrous
-
the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.
- 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).
- seasonal breeding
-
breeding is confined to a particular season
- year-round breeding
-
breeding takes place throughout the year
- sexual
-
reproduction that includes combining the genetic contribution of two individuals, a male and a female
- fertilization
-
union of egg and spermatozoan
- external fertilization
-
fertilization takes place outside the female's body
- oviparous
-
reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.
- saltatorial
-
specialized for leaping or bounding locomotion; jumps or hops.
- nocturnal
-
active during the night
- motile
-
having the capacity to move from one place to another.
- 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.
- solitary
-
lives alone
- 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
- visual
-
uses sight to communicate
- acoustic
-
uses sound 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
- visual
-
uses sight to communicate
- tactile
-
uses touch to communicate
- acoustic
-
uses sound to communicate
- chemical
-
uses smells or other chemicals to communicate
- phytoplankton
-
photosynthetic or plant constituent of plankton; mainly unicellular algae. (Compare to zooplankton.)
- 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.
- carnivore
-
an animal that mainly eats meat
- insectivore
-
An animal that eats mainly insects or spiders.
- 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.
References
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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 .
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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/ .
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