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)
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)
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)
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)
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)
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)
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 feed on algae, inorganic particles, and diatoms. (Dubois, 2003; Parker and Goldstein, 2004)
Checkered garter snakes, painted turtles, and great-tailed grackles have been observed eating adult and tadpole . 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)
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. can also contract the deadly chytrid fungus. Some scientists speculate that the introduction of 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)
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.
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.
living in the southern part of the New World. In other words, Central and South America.
uses sound to communicate
living in landscapes dominated by human agriculture.
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.
an animal that mainly eats meat
uses smells or other chemicals to communicate
to jointly display, usually with sounds, at the same time as two or more other individuals of the same or different species
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.
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.
animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature
fertilization takes place outside the female's body
union of egg and spermatozoan
mainly lives in water that is not salty.
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.
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.
An animal that eats mainly insects or spiders.
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).
marshes are wetland areas often dominated by grasses and reeds.
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.
having the capacity to move from one place to another.
the area in which the animal is naturally found, the region in which it is endemic.
active during the night
reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.
photosynthetic or plant constituent of plankton; mainly unicellular algae. (Compare to zooplankton.)
the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.
Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).
specialized for leaping or bounding locomotion; jumps or hops.
scrub forests develop in areas that experience dry seasons.
breeding is confined to a particular season
reproduction that includes combining the genetic contribution of two individuals, a male and a female
living in residential areas on the outskirts of large cities or towns.
uses touch to communicate
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).
Living on the ground.
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
the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.
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.
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.
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.
uses sight to communicate
breeding takes place throughout the year
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Sanders, O. 1973. A New Leopard Frog from Southern Mexico. Journal of Herpetology, Vol. 7 / 2: 87-92.
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Sterner, R. 2005. "Elevation Map of United States" (On-line). Accessed March 20, 2010 at http://birell.org/andrew/reliefMaps/.
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