More Information

Additional Information

Lithobates palustrisPickerel Frog

By Annie Rudasill

Geographic Range

The pickerel frog (Lithobates palustris) is found throughout much of the eastern United States and parts of southeastern Canada. It is found as far north as New Brunswick, Nova Scotia, and the Upper Peninsula of Michigan. The range extends as far south as South Carolina and westward into northern Alabama, Mississippi, and eastern Texas. The pickerel frog is abundant along the east coast and is found as far west as Missouri. While it is found in northern Georgia, it is almost entirely absent from Florida. (IUCN SSC Amphibian Specialist Group, 2015; Schaff and Smith, 1970)

Habitat

The pickerel frog is found in a variety of temperate freshwater habitats. In northern regions, the pickerel frog can be found in clear, cool waters of lakes, ponds, streams, or pools. In southern regions, it can be found in warmer waters of swamps and rivers. The distribution in many southern and midwestern states is almost entirely dependent on limestone cave habitats, without which the pickerel frog likely could not survive in these areas. The pickerel frog has been reported to overwinter in these cave habitats, which supply a source of cool and clear water and provide protection from harsh environmental conditions. In some states, the pickerel frog has also been found overwintering in abandoned mines. In warmer months, the pickerel frog can be found in some terrestrial habitats such as fields, grasslands, or wooded areas. (DeGraff and Rudis, 1983; Schaff and Smith, 1970)

  • Aquatic Biomes
  • lakes and ponds
  • rivers and streams
  • temporary pools
  • Other Habitat Features
  • caves

Physical Description

Adult pickerel frogs generally have seven pairs of black or brown dorsal spots between their dorsolateral folds, as well as a spot on their snout. Variation is present across geographic gradients, and can include different numbers of dorsal spots, presence or absence of a snout spot, the degree of fusion of dorsal spots, and the overall pattern of dorsal spots. General body color is gray or tan, while the ventral side of the body is white or yellow. There is a white line present on the upper lip, and hind legs are usually banded with black or dark brown stripes. The average size of adults is between 44 to 75 mm SVL (snout-vent length), with a max SVL of 87 mm. There is some sexual dimorphism between males and females, as females are generally reported to be larger in size, though specific measurements are not known. During mating season, males have enlarged thumb pads, which makes them easily identifiable.

Lithobates palustris tadpoles may exhibit a variety of colorations, including green, brown, or gray. They may or may not have spots scattered along the dorsal side, but usually have a light or iridescent ventral side. Length of tadpoles ranges from 5 to 8 cm. (Hunter, et al., 1999; Schaff and Smith, 1970; Trauth, et al., 2004)

  • Sexual Dimorphism
  • female larger
  • Range length
    87 (high) mm
    3.43 (high) in
  • Average length
    60 mm
    2.36 in

Development

The eggs of the pickerel frog are laid in clusters on submerged twigs or stems, and can develop in waters as cool as 8°C and as warm as 29°C. Clusters are firm and are 5-10cm across. Individual eggs are enclosed in gel and measure between 3.6 and 5mm in diameter. Eggs hatch between 11 and 21 days. The pickerel frog remains a tadpole for roughly 3 months, at which point metamorphosis occurs. Length of tadpoles ranges from 5 to 8 cm. The pickerel frog grows indeterminately, with adults reaching up to 87 mm SVL (snout-vent length). (Hunter, et al., 1999)

Reproduction

Male and female pickerel frogs gather in large groups to mate. Males croak on land by the water's edge as well as underwater to attract females. When a male has successfully attracted a female, he will hold the female in amplexus, an embrace in which the male grasps the female with his front limbs from behind and externally fertilizes the eggs as they are released. In the case of the pickerel frog, amplexus is pectoral. (Brandt, 1936; Hunter, et al., 1999)

Pickerel frogs breed yearly in pools, ponds, lakes or other bodies of standing water between February and May. During mating, females cling to submerged twigs and stems and deposit between 2,000 and 3,000 eggs in a clump on the twig or stem, which are fertilized by males during amplexus. Eggs hatch in 11 to 21 days, and individuals remain in the tadpole stage for 3 months. Because pickerel frogs are considered to provide little to no care for offspring, it is assumed that tadpoles are independent at hatching. After transformation, pickerel frogs are generally 2.5 cm in length. (Given, 2005; Hunter, et al., 1999; Wright and Wright, 1949)

  • Breeding interval
    Once yearly
  • Breeding season
    February-May
  • Range number of offspring
    2,000 to 3,000
  • Range time to hatching
    11 to 21 days
  • Average time to independence
    0 days
  • Average age at sexual or reproductive maturity (female)
    unknown years
  • Average age at sexual or reproductive maturity (male)
    unknown years

There is no information on the level of parental care provided by the pickerel frog, but most anuran species are thought to provide little to no care. (Beck, 1998; Elliott, 2004; Stuart, et al., 2008)

  • Parental Investment
  • no parental involvement

Lifespan/Longevity

The lifespan of the pickerel frog is unknown. Similar frogs in the Lithobates genus, such as the northern leopard frog (Lithobates pipiens), are known to live up to 5 years in the wild and 9 years in captivity. (Lannoo, 2005)

Behavior

The pickerel frog congregates near bodies of water after hibernation and remains there during the mating season. After the mating season ends, the pickerel frog may migrate out into fields and woods where it lives a mostly solitary lifestyle. During mating season, the pickerel frog is most active at night, but may be active during the day after mating season ends. The pickerel frog hibernates during winter months, although it goes into hibernation much later than the visually-similar northern leopard frog (Lithobates pipiens) and may be somewhat mobile during winter months. The pickerel frog is usually found in the substrate of ponds during hibernation, although it can overwinter in abandoned mines or caves as well. In general, the pickerel frog is not territorial, but males may call aggressively to other males while defending calling spots during the mating season. (Brandt, 1936; DeGraff and Rudis, 1983; Given, 2005; Hunter, et al., 1999)

Home Range

There are no studies that name a specific home range for the pickerel frog.

Communication and Perception

The call of the pickerel frog is described as a short snoring sound, lasting an average two seconds in length at 1222 Hz. The male pickerel frog will vocalize calls to attract females during mating season. Like many anuran species, the pickerel frog utilizes the same calling spot each night during mating season, and calling choruses can last upwards of five hours. Typically, the male pickerel frog will broadcast into the air, but some instances of underwater calling have been documented in disturbed habitats.

In addition to a mating call, the pickerel frog has been documented utilizing two aggressive vocalizations in male-to-male interactions. These calls have been described by Given (2004) as a "growl" and a "snicker." Both calls are shorter in duration than the mating call, lasting an average of 1.3 seconds or 0.21 seconds, respectively. (Given, 2005; Given, 2008; VanDeWalle, 2011)

Food Habits

Pickerel frogs are carnivorous, and are generally known to rely on terrestrial arthropods as a main food source, specifically insects and arachnids. Other food sources include snails, crayfish, isopods and aquatic amphipods, but these organisms only make up roughly 5% of their diet. In cave systems in the Ozark Mountains, pickerel frogs have been observed eating stream isopods, although they are not considered to be a significant threat to stream isopods in these caves. (DeGraff and Rudis, 1983; Fenolio, et al., 2005)

  • Animal Foods
  • insects
  • terrestrial non-insect arthropods
  • other marine invertebrates

Predation

Data on pickerel frog predation are limited, but there are recorded instances of the pickerel frog being used as bait for pickerel (Esox spp.). There have also been observations of predation by bald eagles (Haliaeetus leucocephalus) and minks (Neovison vison), as well as bullfrogs (Lithobates catesbeianus) and green frogs (Lithobates clamitans) in captivity. Despite the yellow warning coloration on the thighs of the pickerel frog, which is exhibited due to toxic skin secretions, it is suspected that the pickerel frog is subject to other vertebrate predators. Tadpoles are also likely to be prey for many fish and invertebrates. (Hunter, et al., 1999; Lannoo, 2005; VanDeWalle, 2011)

Ecosystem Roles

Like many anurans, the pickerel frog is subject to infection by the amphibian chytrid fungus (Batrachochytrium dendrobatidis). The pickerel frog is also susceptible to various parasites including protozoans (Myxidium serotinum, Nyctotherus cordiformis, Opalina species, and Ichthyophonus species), flukes (such as Echinostoma trivolvis, Brachycoelium salamandrae and Glypthelmins quieta), parasitic flatworms (Mesocestoides species), nematodes (Abbreviata species, Cosmocercoides variabilis, and Oswaldocruzia pipiens), and trombiculid mites (Hannemania species). Studies on the rate of infection in the pickerel frog are limited, but pickerel frog populations are generally stable. The pickerel frog provides food web stability because of its role as an insectivore and as a prey item for fish, birds, and other predators. (Davidson and Chambers, 2011; Jones, et al., 2013; Lannoo, 2005; Orlofske, et al., 2009)

Commensal/Parasitic Species
  • protozoans (Myxidium serotinum)
  • protozoans (Nyctotherus cordiformis)
  • protozoans (Opalina species)
  • protozoans (Ichthyophonus species)
  • flukes (Echinostoma trivolvis)
  • flukes (Brachycoelium salamandrae)
  • flukes (Glypthelmins quieta)
  • parasitic flatworms (Mesocestoides species)
  • nematodes (Abbreviata species)
  • nematodes (Cosmocercoides variabilis)
  • nematodes (Oswaldocruzia pipiens)
  • trombiculid mites (Hannemania species)

Economic Importance for Humans: Positive

The pickerel frog has been used as fishing bait by humans. Like most other anurans, it is likely that the pickerel frog provides regulating services in the form of pest control because it is an insectivore, and may potentially contribute to disease control through consumption of mosquitoes. However, such contributions have not been scientifically demonstrated. (Lannoo, 2005)

  • Positive Impacts
  • body parts are source of valuable material

Economic Importance for Humans: Negative

The pickerel frog is poisonous. It secretes toxins through its skin, which can be harmful to humans and pets if ingested. (Lannoo, 2005; Schaff and Smith, 1970)

Conservation Status

The pickerel frog is listed by the IUCN as "Least Concern." The pickerel frog is not given any special conservation status on the US Federal List or CITES. With thousands of sub-populations and a wide range of habitats, the pickerel frog population is considered stable, although there are localized pickerel frog declines in many states including Iowa, Wisconsin, Minnesota, and Kansas, as well as Ontario, Canada. The pickerel frog is subject to infection by amphibian chytrid fungus (Batrachochytrium dendrobatidis) as well as several ranaviruses, but these diseases have not resulted in significant population declines. Pickerel frog habitat is subject to clearcutting and urbanization, which likely affects sub-populations. While species-specific legislation is not in place for the pickerel frog, it seems to benefit indirectly from some government programs such as the Wetland Reserve Program. (IUCN SSC Amphibian Specialist Group, 2015; Lannoo, 2005; Waddle, et al., 2012)

Contributors

Annie Rudasill (author), Radford University, Cari Mcgregor (editor), Radford University, Zeb Pike (editor), Radford University, Karen Powers (editor), Radford University, April Tingle (editor), Radford University, Jacob Vaught (editor), Radford University, Tanya Dewey (editor), University of Michigan-Ann Arbor.

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

acoustic

uses sound to communicate

aposematic

having coloration that serves a protective function for the animal, usually used to refer to animals with colors that warn predators of their toxicity. For example: animals with bright red or yellow coloration are often toxic or distasteful.

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.

bog

a wetland area rich in accumulated plant material and with acidic soils surrounding a body of open water. Bogs have a flora dominated by sedges, heaths, and sphagnum.

carnivore

an animal that mainly eats meat

choruses

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

diurnal
  1. active during the day, 2. lasting for one day.
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

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

freshwater

mainly lives in water that is not salty.

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.

indeterminate growth

Animals with indeterminate growth continue to grow throughout their lives.

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.

migratory

makes seasonal movements between breeding and wintering grounds

motile

having the capacity to move from one place to another.

natatorial

specialized for swimming

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.

poisonous

an animal which has a substance capable of killing, injuring, or impairing other animals through its chemical action (for example, the skin of poison dart frogs).

polygynandrous

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

saltatorial

specialized for leaping or bounding locomotion; jumps or hops.

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

swamp

a wetland area that may be permanently or intermittently covered in water, often dominated by woody vegetation.

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.

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

References

Beck, C. 1998. Mode of fertilization and parental care in anurans. Animal Behavior, 55/2: 439-449.

Brandt, B. 1936. The frogs and toads of eastern North Carolina. Copeia, 1936/4: 215-223.

Cassie, B. 1999. National Audubon Society First Field Guide: Amphibians. New York, NY: National Audubon Society.

Davidson, S., D. Chambers. 2011. Occurrence of Batrachochytrium dendrobatidis in amphibians of Wise County, Virginia, USA. Herpetological Review, 42/2: 214-215.

DeGraff, R., D. Rudis. 1983. Amphibians and Reptiles of New England, Habitats and Natural History. Amherst, MA: University of Massachusetts Press.

Duellman, W., L. Trueb. 1986. Biology of Amphibians. Baltimore, MD: The Johns Hopkins University Press.

Elliott, L. 2004. The Calls of Frogs and Toads. Mechanicsburg, PA: Stackpole Books.

Fenolio, D., G. Graening, J. Stout. 2005. Seasonal movement pattern of pickerel frogs (Rana palustris) in an Ozark cave and ecological implications supported by stable isotope evidence. The Southwestern Naturalist, 50/3: 385-389.

Given, M. 2008. Does physical or acoustical disturbance cause male pickerel frogs, Rana palustris, to vocalize underwater?. Amphibia-Reptilia, 29/2: 177-184.

Given, M. 2005. Vocalizations and reproductive behavior of male pickerel frogs, Rana palustris. Journal of Herpetology, 39/2: 223-233.

Hardy, L., L. Raymond. 1991. Observations on the activity of the pickerel frog, Rana palustris, in northern Louisiana. Journal of Herpetology, 25/2: 220-222.

Hocking, D., K. Babbitt. 2014. Amphibian contributions to ecosystem services. Herpetological Conservation and Biology, 9/1: 1-17.

Hoverman, J., M. Gray, D. Miller. 2010. Anuran susceptibilities to ranaviruses: role of species identity, exposure route, and a novel virus isolate. Diseases of Aquatic Organisms, 89/1: 97-107.

Hunter, M., A. Calhoun, M. McCollough. 1999. Maine Amphibians and Reptiles. Onrono, ME: University of Maine Press.

IUCN SSC Amphibian Specialist Group, 2015. "Lithobates palustris" (On-line). The IUCN Red List of Threatened Species 2015. Accessed January 29, 2016 at http://www.iucnredlist.org/details/58690/0.

Jones, E., K. Hyde, K. Pang. 2013. Freshwater Fungi and Fungal-like Organisms. Berlin, Germany: DeGruyter.

Lannoo, M. 2005. Amphibian Declines: The Conservation Status of United States Species. Oakland, CA: University of California Press.

McAllister, C., S. Trauth, C. Bursey. 1995. Parasites of the pickerel frog, Rana palustris (Anura: Ranidae) from the southern part of its range. The Southwestern Naturalist, 40/1: 111-116.

Moore, J. 1939. Temperature tolerance and rates of development in eggs of amphibia. Ecology, 20/4: 459-478.

Orlofske, S., L. Belden, W. Hopkins. 2009. Moderate Echinostoma trivolvis infection has no effects on physiology and fitness-related traits of larval pickerel frogs (Rana palustris). Journal of Parasitology, 95/4: 787-792.

Schaff, R., P. Smith. 1970. Geographic variation in the pickerel frog. Herpetologica, 26/2: 240-254.

Schaff, R., P. Smith. 1971. Rana palustris (LeConte) pickerel frog. Catalog of American Amphibians and Reptiles, 117/1: 1-3.

Stuart, S., M. Hoffman, J. Chanson, N. Cox, R. Berridge, P. Ramani, B. Young. 2008. Threatened Amphibians of the World. Barcelona, Spain: Lynx Edicions.

Trauth, S., H. Robison, M. Plummer. 2004. The Amphibians and Reptiles of Arkansas. Fayetteville, AR: The University of Arkansas Press.

VanDeWalle, T. 2011. Frogs and Toads in Your Pocket: A Guide to Amphibians of the Upper Midwest. Iowa City, IA: University of Iowa Press.

Waddle, J., B. Glorioso, S. Faulkner. 2012. A quantitative assessment of the conservation benefits of the Wetlands Reserve Program to amphibians. Restoration Ecology, 21/2: 200-206.

Wright, A., A. Wright. 1949. Handbook of Frogs and Toads of the United States and Canada. Ithaca, NY: Comstock Publishing Co.

Search

Navigation Links

Information
Pictures
Sounds
Classification

Classification