Northern Leopard Frog

Lithobates pipiens (Rana pipiens)

Northern Leopard Frog

Distribution in Wyoming

 

 

 

 

 

 

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The Northern Leopard Frog is widely distributed across most of North America (except along the west coast), from the middle of Canada deep into Mexico. It is found throughout most of Wyoming (except the extreme northwest corner), where it inhabits the permanent water bodies of the prairie, foothill, and montane life zones below 9,000 feet. It prefers the small ponds and cattail marshes at lower elevations or the beaver ponds and boggy meadows higher in the mountains. It is a highly aquatic species but can be found foraging in the vicinity of sedges and tall grass adjacent to permanent water.

They frequently are observed lounging the grassy margins of ponds but they are alert and keen to dive into the water when alarmed. They scoot along the bottom (away from the shoreline) for about 4-5 feet where they then either wait out the intruder, or they do a little 180 flip and return submerged to their previous location, ease their eyes and snout tip through the water’s surface, and peek at the surroundings for danger.

Northern Leopard Frog Northern Leopard Frog

This is a lanky, thin-waisted, and long-legged frog. It is 3-4 inches long (SVL) and has a pointed snout. Its back is covered with spots consisting of black ovals with white margins; these spots extend down along the sides and on to the legs. The dorsal surface is green or brown and the ventral surface is white. It has a white or tan dorsolateral fold (a pucker of skin forming a delineation between the back and the sides) beginning behind the eye and extending along the body to the waist. It also has a white stripe running along the upper jaw and continuing back to the shoulder. Its tympanic membrane is distinct and about the same size or slightly smaller than the diameter of the eye.

Northern Leopard Frog Northern Leopard Frog

Breeding activities get underway in early spring (April-May in the lowlands and well into June at higher elevations) and are brought on more by warming temperatures than by spring rains. Males have two vocal sacs, one on each side of the throat, which they inflate and flutter when emitting a repertoire of chirps, grunts, and guttural chuckles: to declare their territory to other males and to advertise their availability to females. Males have enlarged thumbs (nuptial pads) which are used to help hold the slippery and slightly larger females during mating.

Northern Leopard Frog Northern Leopard Frog

Each of the 500 to several 1000 black and white eggs is enclosed within two gelatinous capsules and they collectively form a large globular mass. The cluster is usually attached to submerged vegetation and rests just below the surface of the water. Multiple egg masses from different breeding pairs are often found together in the clear, clean water of communal breeding areas. The eggs hatch in 5-10 days and tadpoles undergo metamorphosis 8-12 weeks later. Sexual maturity is reached in 2-3 years.