Lowland leopard frogs (Lithobates yavapaiensis) are a Nearctic species found in the southwestern United States and northern Mexico. This area includes central Arizona, west to southern California and southern Nevada. Their range continues eastward into western New Mexico. Although these frogs were historically found in New Mexico and the Imperial valley of California (Imperial and Riverside counties), they are believed to be extirpated from both areas. (Lannoo, 2005)
Lowland leopard frogs live in and around aquatic habitats in arid canyons and desert scrubland. These habitats can be amid conifer-dominated forests, as well. Adults inhabit streams, beaver ponds, springs, riverbanks, and deeper pools with thick vegetation. They also make use of man-made structures like water troughs or man-made pools. Areas like hot springs are especially important for breeding habitat, as they provide winter breeding grounds and allow continued activity in the winter.
While in the egg and tadpole stages, they are found more frequently in areas with slow-moving or stagnant water, like pools or marshy habitats. These areas typically contain more protective vegetative cover. Lowland leopard frogs can also tolerate brackish water (6-9% typically in range), provided there is a source of freshwater nearby. Adults can live in water with a salinity of up to 13%, but eggs cannot survive above a salinity of 5%. They live at an elevation of 146m to 1817m. (Lannoo, 2005; "Species accounts for the Lower Colorado River multi-species conservation program", 2016)
Adult male lowland leopard frogs reach a snout-vent length (SVL) of 4.6 to 7.2cm while females measure 5.3 to 8.7cm. Males are generally smaller than females of the same age. Mass is not reported. This species' color ranges from brown to green with dark marking all over their bodies. They specifically have dark larger spots on their bodies with a pale outline. The marking on the rest of their bodies includes dark spots on the belly, throat, and thighs. It is possible to also find light spots on their thighs as well.
As tadpoles, they reach a length of 77mm, with their tail being twice as long as their body. They possess a pale green or pale yellow hue, with the ventral portions being lighter shaded. Their tail is grey and their main body has dark speckling. The fins are yellowish-white with dark speckling. At the time of metamorphosis, their SVL is 2.5 to 2.9cm.
Males reach sexual maturity at snout-vent lengths of ca. 5.3 cm, while it is still unknown when females reach sexual maturity. (Bartlett and Bartlett, 2013; Dodd, 2013; Lannoo, 2005)
Eggs are aquatic, with eggs fertilized externally by males. Eggs are laid just under the surface of the water attached to vegetation, sticks, or rocks. Eggs are placed in clusters and each egg is spherical and the eggs are in a jelly mass of ca. 75mm in diameter. Eggs hatch after 15-18 days (at 14 °C), and tadpoles hatch with external gills, eyes, and a tail. Normal developmental rates occur at water temperatures of 11°C to 29 °C. They remain as tadpoles for 3-9 months until they reach a total length of 77mm; after metamorphosing, their SVL is 25-29mm. These frogs can grow to a SVL of 75-90mm. Males reach sexual maturity at SVL of 53.5mm. Adults grow indeterminately, although their growth rate is affected by temperature. Males are smaller than females of the same age. (Dodd, 2013; "Lowland Leopard Frog (Rana = Lithobates yavapaiensis) basic conceptual ecological model for the Lower Colorado River", 2020; "Species accounts for the Lower Colorado River multi-species conservation program", 2016)
Lowland leopard frogs have a polygynandrous mating system. The timing of lowland leopard frogs' breeding season is dictated by water temperature; most breeding occurs at water temperatures between 10-18 °C. At lower elevations where it is warmer or by hot springs, they can reproduce and remain active year-round. At high elevations where cooler temperatures prevail, these frogs reproduce in the spring (January to March) and again in the fall (September to October; the latter at lower rates).
Males attract females by vocal calls. Intensity of calls depends on water temperature and rain fall. They reproduce in amplexus, with external fertilization. The eggs are then left to hatch on their own. ("Lowland Leopard Frog (Rana = Lithobates yavapaiensis) basic conceptual ecological model for the Lower Colorado River", 2020; "Species accounts for the Lower Colorado River multi-species conservation program", 2016)
Lowland leopard frogs reproduce seasonally in the spring (January to March) and in the fall (September to October) at cooler temperatures and year-round in warmer climates (10 to 18 °C). They reproduce with external fertilization, leaving clusters of underwater eggs attached to sticks, rocks, or plants just below the water surface. Eggs hatch in 15 to 18 days (at 14 °C) and the young are fully independent. Metamorphosis usually takes place 3 to 9 months after hatching. Sexual maturity is reached in males at a SVL of 53.5mm but sexual maturity in females is unknown. Breeding interval is unreported, and hatching mass is unknown. The number of offspring per clutch is unreported but collections from Sosa et al.(2009) suggest that it is greater than 100 eggs/clutch. However, egg masses laid and fertilized earlier in the spring may have twice the number of eggs as those later in the season. (Dodd, 2013; "Lowland Leopard Frog (Rana = Lithobates yavapaiensis) basic conceptual ecological model for the Lower Colorado River", 2020; Sosa, et al., 2009; "Species accounts for the Lower Colorado River multi-species conservation program", 2016)
After external fertilization, the parents leave the eggs attached to sticks, rocks, and aquatic plants. Beyond this act, there is no parental investment for both sexes. (Dodd, 2013)
Lifespan is not reported for lowland leopard frogs but others in the genus like northern leopard frogs (Lithobates pipiens) are reported to live a maximum of 9 years in the wild. Northern leopard frogs also have an expected life span of 5 years. Lifespan in captivity is unreported.
In recent years, American bullfrogs (Lithobates catesbeianus) have led to a decrease in lowland leopard frog populations by predation. Lowland leopard frogs have a seasonal pattern with age showing that survival rates in the winter are lower than other seasons. (Lannoo, 2005; Smirina, 1994)
Male lowland leopard frogs call nocturnally. These frogs are primarily aquatic (swimming) but can hop across land and on banks. They are also social and often inhabit bodies of water with conspecifics. Although it is rare, lowland leopard frogs can breed with other similar species of frog, like Chiricahua leopard frogs (Lithobates chiricahuensis), northwest Mexico leopard frogs (Lithobates magnaocularis), or northern leopard frogs (Lithobates pipiens). These pairings create sterile F1 hybrids.
Male lowland leopard frogs are very vocal, with a complex advertisement call. The call is a trill 3-8 s long, comprised of 6-16 notes. The time between notes progressively gets shorter. They are broadcast at a typical frequency of 1.8 kilohertz. Rainfall and water temperature are environmental cues for increasing seasonal activity.
These frogs are not known to migrate. There have not been any studies on hibernation or torpor, although those individuals living in hot springs are active year-round.
Larvae are believed capable of learning. Captive studies found the tadpoles can recognize potential novel predators (fish) and respond by swimming faster (as a means of escape). (Dodd, 2013; Lannoo, 2005; "Species accounts for the Lower Colorado River multi-species conservation program", 2016)
Although the home range of lowland leopard frogs has not been reported, northern leopard frogs (Lithobates pipiens) in the summer do stay in a distinguishable area and often return to it. Northern leopard frogs' daily movements are typically less than 10m a day; similar sedentary lifestyles may be assumed for lowland leopard frogs. (Lannoo, 2005)
Lowland leopard frogs communicates with other frogs with vocalizations. These frogs' calls are usually rapid and are usually low pitched. They are often trill-like in sound, though Bartlett and Bartlett (2013) described the call like "rubbing your hand back and forth on a wet balloon." These calls usually only last 3 to 8 seconds and have 6 to 15 notes, with an average frequency of 1.8 kHz. The notes become quicker as the duration of the call increases. There is some evidence of perception of pheromones as tadpoles can detect predators by chemical cues.
There is little information about visual or tactile communication. However, as all frogs reproduce with external fertilization via amplexus, it is assumed that tactile communications exist. (Bartlett and Bartlett, 2013; Dodd, 2013; Lannoo, 2005)
Little is known about the diet of lowland leopard frogs. Larvae are herbivorous, but studies of adult diets have not been performed. Researchers assume that adults are opportunistic insectivores, consuming aquatic invertebrates and some select vertebrates when available. (Dodd, 2013; Lannoo, 2005)
Common predators of lowland leopard frogs in the tadpole state include insects, fish, great blue herons (Ardea herodias), Sonora mud turtles (Kinosternon sonoriense), tiger salamanders (Ambystoma tigrinum) and garter snakes (Thamnophis). Predators of adults include black hawks (Buteogallus anthracinus), ringtail cats (Bassariscus astutus), mountain lions (Puma concolor), bobcats (Lynx rufus), raccoons (Procyon lotor), American badgers (Taxidea taxus), skunks (family Mephitidae), gray foxes (Urocyon cinereoargenteus), coyotes (Canis latrans), and black bears (Ursus americanus).
Lowland leopard frogs have two main ways of defending against predators: camouflage and active escape tactics. In the latter, these lowland leopard frogs will retreat to deeper waters where it is relatively safe. Tadpoles can also detect chemical differences when predators are near and signals them to hide or swim away. (Lannoo, 2005; Dodd, 2013; Lannoo, 2005; "Species accounts for the Lower Colorado River multi-species conservation program", 2016)
Lowland leopard frogs in the tadpole state are herbivores. In the adult phase, they are presumed to consume insects and some non-insect invertebrates. Predators include regional mammals, reptiles, birds, and fish. Parasites of the lowland leopard frog include some trematodes like Cephalogonimus brevicirrus, Gylpthelmins quieta, Haematoloechus complexus, and Megalodiscus temperatus. They are also parasitized by nematodes, including Falcaustra catesbeiane, Rhabdias ranae, and Physaloptera. (Dodd, 2013; Goldberg, et al., 1998; Lannoo, 2005; "Species accounts for the Lower Colorado River multi-species conservation program", 2016)
Lowland leopard frogs have no reported positive economic effect on humans.
Lowland leopard frogs have no reported negative economic effects on humans.
The IUCN Red List has lowland leopard frogs listed as "Least Concern." These frogs have no special status on the United States Endangered Species list. CITES or the State of Michigan list do not have special statuses for lowland leopard frogs. This species is listed in Arizona under the "S3" (vulnerable) classification and protective laws have been put in place to protect this species in Arizona, California under the "SX" (presumed extirpated) classification, in New Mexico as "S1" (critically imperiled) and "SNR" (no status rank) in Utah. In 1995 a survey was completed of 6 sites in this species historical range and numerous other sites resulting in no findings. In California lowland leopard frogs have been listed as endangered as well as in New Mexico. They have not been documented in California since 1965.
Lowland leopard frogs are under threat from habitat fragmentation and loss of land and water to agriculture and climate change. Changing of water sources from agriculture has led to critical habitat fragmentation. Lowland leopard frogs are no longer in 50% of their historical range. Locally-invasive species like American bullfrogs (Lithobates catesbeianus) have also been responsible for a decrease in lowland leopard frog numbers due to predation. Another major problem facing lowland leopard frogs is chytridiomycosis which is an infection caused by a fungus (Batrachochytrium dendrobatidis) that affects the frogs skin. The keratin dries, reducing gas and water exchange across the skin. Early signs of this infection include anorexia or lethargy. Between 1992 and 1993 this infection caused 50%-80% mortality rates in metamorphosed frogs in some populations. These frogs can hybridize, although it is rare, and offspring are usually sterile.
Lowland leopard frogs are protected in areas like Gila National Forest which is in this species' historical range. In Mexico, more data are needed such as finding a range wide abundance and learning specific threats to this species. In Mexico, these frogs do have "special protection" and have been listed as rare in Mexico. Since 1995, special restrictions have been put in place to protect this species. In 1991, in the U.S., these frogs were considered a category 2 candidate species by the United States Fish and Wildlife Service. However, when Category 2 was dropped as a category, lowland leopard frogs were removed from listing consideration. There is a breeding program for lowland leopard frogs at the Phoenix Zoo. (Dodd, 2013; Lannoo, 2005; Santos-Barrera and Hammerson, 2004; "Species accounts for the Lower Colorado River multi-species conservation program", 2016)
Ian Wilson (author), Radford University, Sierra Felty (editor), Radford University, Bianca Plowman (editor), Radford University, Karen Powers (editor), Radford University, Victoria Raulerson (editor), Radford University, Christopher Wozniak (editor), Radford University, Genevieve Barnett (editor), Colorado State University.
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.
uses sound to communicate
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
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.
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.
An animal that eats mainly plants or parts of plants.
Animals with indeterminate growth continue to grow throughout their lives.
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.
This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.
specialized for swimming
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.
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.
breeding is confined to a particular season
remains in the same area
reproduction that includes combining the genetic contribution of two individuals, a male and a female
associates with others of its species; forms social groups.
living in residential areas on the outskirts of large cities or towns.
uses touch to communicate
Living on the ground.
uses sight to communicate
breeding takes place throughout the year
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