Distinguishing Features
The Northern Leopard Frog is a slim,
medium-sized brown or green frog with large "leopard-like"
dark brown or olive coloured spots on the back, sides and legs.
The overall colour may be grass green or light brown. The prominent
spots vary in size and number, and may be randomly scattered or
arranged in two or three rows down the back. The spots have dark
edges and light outside halos. The legs are long and the body has
prominent dorso-lateral folds that are creamy-coloured and extend
along the full length of the back. The belly is white and unmarked.
Males range between 50 and 80 mm; females are slightly larger. Very
vocal with a large repertoire of calls. (Green and Campbell, 1984).
Distribution
Columbia Basin: Found only in the
Creston Valley.
British Columbia: Known only from
the Creston area. Has disappeared from all previously inhabited
sites in the East Kootenays and Okanagan Valley. Rare in the Creston
Valley, where it was common in the 1970s. (Cannings et al. 1999).
Global: From Maine and Nova Scotia
west through the northern U.S. and southern Canada to British Columbia,
Washington, Oregon and California (Green and Campbell 1984).
Habitat
The Northern Leopard Frog occurs
in and around marshes, wet meadows and riparian areas with thick
vegetation that the adults use for cover.
Threats
Preliminary surveys
reveal that the Northern Leopard Frog does not occur in any of the
sites where it was relatively common in the 1970s. Reasons for the
decline are unknown - predatory fish introduction may be a factor.
Throughout large portions of its range this species is thought to
be declining for such reasons as habitat degradation, introduction
of predatory aliens (fish and bull frogs), massive collections for
scientific research and educational purposes as well as seemingly
unexplained declines (Cannings et al. 1999).
Biology
They breed in ponds or lake edges,
or even temporary wetlands with dense emergent vegetation to which
they will attach their egg masses well below the surface of the
water. The males start calling with a range of grunts, putters and
rumbles early in the spring when the ice melts off of the ponds.
The tadpoles stay in the thick vegetation as they develop, taking
2-3 years to reach maturity. They spend the winter hibernating on
the bottom of ponds and sluggish streams. If they have bred in a
temporary wetland, they will migrate to a more permanent wetland
after the breeding season. Northern Leopard Frogs feed on insects,
leeches, fish, spiders and a variety of invertebrates. They are
in turn preyed upon by such predators as Raccoons, snakes, Bullfrogs
and herons. (Cannings et al. 1999).
