Lithobates palustris (LeConte, 1825)

Scientific Classification and Basic Identification

The pickerel frog, scientifically named Lithobates palustris (formerly Rana palustris), is a small North American frog. It is recognizable by the seemingly 'hand-drawn' square markings on its dorsal back.

Western Range Extent

The pickerel frog's range extends west from most of Wisconsin, southeastern Minnesota, and eastern Iowa, through Missouri, down to eastern Texas.

Eastern Range Extent

To the east, it stretches through northern Louisiana, most of Mississippi, northern Alabama, Georgia, and South Carolina, reaching the Atlantic coast.

Northern Range Extent

Its northern range extends into Canada, covering the southern regions of Ontario, Quebec, New Brunswick, and Nova Scotia; individuals have also been spotted in Newfoundland and Labrador, Canada.

Midwestern Distribution Note

Across midwestern states, the species' distribution is spotty, so a local field guide should be consulted for detailed range information in specific areas.

General Habitat Range

Pickerel frogs live in a variety of habitats.

Northern Population Habitat Preferences

Northern populations prefer areas near cold, clear water, including rocky ravines, bogs, and meadow streams, and can also be found around heavily wooded lakes and rivers. A study of Canadian amphibians found that pickerel frogs are negatively associated with young forest stands.

Southern Population Habitat Preferences

Southern populations within the species' range prefer warmer waters, such as those found in Coastal Plain and floodplain swamps. They are most often seen along the edges of streams, lakes, rivers, and even flooded ditches.

Winter Hibernation Basics

During winter, pickerel frogs hibernate under silt and debris in their aquatic habitats, and are generally only active between April and October. When possible, this species uses caves as thermal refugia during the coldest months of the year.

Cave Association Classification

The pickerel frog is a trogloxene species, meaning it occurs in caves but cannot complete its full life cycle there. While the species is most abundant in caves during winter, it can be active deep inside caves at almost any time of year.

Cave Hibernation Behavior

When temperatures drop too low, the species occupies clustered hibernacula, which are commonly grouped near each other in the center of caves. Pickerel frogs may also use these same caves to escape heat during hot summers.

Breeding Water Preferences

For breeding, pickerel frogs still prefer cool, clear water. They can breed in both temporary and permanent ponds, but appear to favor ponds with long to permanent water retention.

Rhode Island Breeding Habitat Observations

In Rhode Island specifically, pickerel frog tadpoles and egg masses have been found in well-vegetated permanent manmade rural ponds, farm ponds, and urban ponds surrounded by roads.

Breeding Season Timing

Pickerel frogs typically emerge from hibernation around mid-April, with most individuals arriving at breeding ponds by early May. No fall reproduction has been recorded for this species.

Breeding Pond Grouping

At breeding ponds, pickerel frogs are usually found in large groups in the water. Their mating behavior is not notably different from that of other ranid frogs.

Male Breeding Call Basics

Males initiate breeding by emitting low-pitched calls, which are often so low that they go unnoticed during standard calling surveys. Males can change their call type depending on interactions with other males, and are known to call while submerged, which usually makes their calls inaudible in open air.

Underwater Call Variation

Underwater calls vary between different populations, which suggests that under some conditions, vocalizing underwater is more beneficial than calling into open air.

Reproduction Method

Pickerel frogs reproduce via external fertilization while engaging in a mating behavior called amplexus. Sometimes amplexus lasts more than one or two days, even after the female has finished depositing her eggs.