The Pickerel frog is a relatively large frog that is often confused with the Northern Leopard Frog (Rana pipiens). However, the Pickerel frog has chocolate-brown spots arranged in two rows between the dorsolateral folds while the Leopard frog's spots are more irregular and scattered. They can be distinguished by the bright yellow or yellow-orange color on the inside concealed surface of the thigh. Leopard frogs are white in the same area. These frogs range in size from 45 to 75 millimeters as adults. Females are usually larger than males. Male Pickerel frogs have paired vocal sacs, stout forearms and swollen thumbs. These frogs produce toxic skin secretions that are irritating to humans but can be fatal to other small animals, especially other amphibians. Many frog-eating snakes avoid these frogs for this reason (Matson 1999).
The Pickerel frog ranges from the Canadian Maritime Provinces south to the Carolinas and then west to southeast Minnesota and eastern Texas. However, there are many gaps in the distribution of these frogs, especially in the southern parts of Ohio, Illinois, and Indiana (Conant and Collins 1998).
Pickerel frogs commonly inhabit cool, wooded streams, seeps and springs although they are also found in many other habitats. In the South, it can also be found in the relatively warm, turbid waters of the Coastal Plain and floodplain swamps. These frogs tend to wander far into grassy fields or into weed-covered areas in the summer (Conant and Collins 1998).
Pickerel frogs breed in late March to early May. Males have low, snore-like calls to attract females. After fertilization, females lay spherical egg masses attached to tree branches in permanent or temporary ponds. These masses may contain from 700 to 3000 eggs. Each egg has an average diameter of 1.6 millimeters when laid. After the eggs hatch, it takes around 87 to 95 days for the tadpoles to transform into small frogs and leave the water. It requires an additional two years before these frogs reach sexual maturity and are able to reproduce (Matson 1999).
Pickerel frogs are nocturnal and rouse from hibernation in early spring. These frogs remain active until the end of October when they burrow into sediments in the bottom of ponds or streams and hibernate for the winter (Bokstanz 1998).
These frogs are carnivorous and their diet consists mostly of small insects and other invertebrates. However, as tadpoles, these frogs are herbivorous (Conant and Collins 1998).
This species does not seem to adversely affect humans at all.
These frogs are not of great economic importance to humans. They are not caught as game and are not commonly kept as pets due to their skin secretions. They are occasionally used as fishing bait for anglers.
The population of Pickerel frogs is listed as stable, and there are no special restrictions on them. However, in many areas populations are declining due to habitat changes.
This species is one of very few poisonous frogs found in the United States (Matson 1999).
Karla Arnold (author), Michigan State University, James Harding (editor), Michigan State University.
Bokstanz, L. 1998. Accessed October 26, 1999 at http://www.zu/utexas.edu/research/txherps/frogs/rana.palustris.html.
Conant, R., J. Collins. 1998. A Field Guide to Reptiles and Amphibians Eastern / Central North America. New York: Houghton Mifflin Company.
Matson, Ph. D., T. "An Introduction to the Natural History of the Frogs and Toads of Ohio" (On-line). Accessed October 26, 1999 at http://www.cmnh.org/research/vertzoo/frogs/palustris.html.