Crawfish Frog (Lithobates areolatus)

Crawfish Frog (Lithobates areolatus)

Alternate names: Rana areolata; Crayfish Frog

by Jeff LeClere

An adult crawfish frog, Lithobates areolatus, from Missouri.
A crawfish frog, Lithobates areolatus, from Missouri.

Status

ENDANGERED and Species of Greatest Conservation Need. It is illegal to kill or collect this species by law in Iowa. This frog has not been seen in Iowa since the early 1940s! It has been found in southeastern Iowa. Any frog suspected of being a crawfish frog should be photographed, the exact location noted, and contact the DNR and/or us immediately!

Description

The crawfish frog is a relatively large Iowa species. They may grow to 3 inches in body length. They are rather squatty with a blunt snout. The ground color is brown, but may range to a light gray in some specimens. They have dark spots about the back and sides. These spots have a light border. Female have a poorly defined dorsolateral ridge, but males have a yellowish ridge and may have yellow on the inner portions of the legs and groin.

The only frogs the crawfish frog could be confused with are the leopard and pickerel frogs. Crawfish frogs have a reticulated upper lip rather than a stripe and are never green as in the northern and southern leopard frogs. Crawfish frogs have a plain light belly.

Subspecies

Lithobates areolatus circulosus, the northern crawfish frog, is the only subspecies found in Iowa.

Range

The crawfish frog has been found only in the following Iowa counties: Van Buren, Jefferson, Davis, Appanose, and Wayne. The most records are from Van Buren County. The remaining counties only have one or two locations documented (Bailey, 1944). This frog has only been reported in Iowa from the late 1930s into the early 1940s. These frogs seem to have disappeared from the state. No new populations have been found and, worse yet, no frogs have been seen from known locations despite intensive surveys. If anyone finds a frog resembling a crawfish frog, note the exact location, get a good photo, and send it to the IA DNR and/or us.

Habitat

Bailey (1943) states that all records of this frog were from ponds in stream valleys. Flooded pastures are also used. Johnson (1992) gives the following habitat description of the crawfish frog in Missouri:, populations occur in or near low-lying hay fields, native grass pastures, prairies, and occasionally river valleys. Crayfish and their burrows are extremely important as refuge for these frogs. The chimneys formed outside the burrows are flattened down into platforms by crawfish frogs that use the burrows. They hide in crayfish burrows after the breeding season.

Habits

Crawfish frogs are active from March to October in states close to Iowa and it could be presumed that this is (was) true in Iowa as well. Bailey (1943) provides the only information on breeding and other activities of this species in Iowa. They call and breed only in April. Several ponds had calling males in mid April. They have a call that sounds like a snorting hog, and several calling males sound like a styful of pigs. This call has surprising carrying power and can be heard for some distance.

The females lay up to 7,000 eggs. The tadpoles hatch about a dozen days later. The tadpoles take two years to transform. They metamorphose in May or June of their second year. After the breeding season, this frog is not found sitting at the edges of ponds or in pools like green or bullfrogs. They are very secretive using crayfish burrows as retreats during the summer outside of the breeding season. Some of the specimens secured in Iowa were taken from crayfish burrows and usually two were present in a single burrow (Bailey, 1943). They have been taken on the road in mid May. Johnson (1992) states that these frogs may be found on the roads at night during a warm heavy rain.

Food

This frog eats any small creature it can swallow, including small crayfish.

An adult crawfish frog, Lithobates areolatus, from Missouri in a burrow.
A crawfish frog, Lithobates areolatus, in a burrow, from Missouri.