Northern Leopard Frog (Rana pipiens)
Description: Northern Leopard Frogs are brown or greenish-brown with beige dorsolateral folds. They tend to have black spots that cover their backs and black stripes on their legs (see above pictures). Their bellies are usually tan, buff, or off-white and their toes are fully webbed. Leopard Frogs are medium to large-sized frogs (2 to 4" snout to rump length, or greater). Leopard Frogs are members of the family Ranidae, which includes other "true frogs" such as Green Frogs and Bullfrogs.
Habitat/Ecology: Leopard Frogs prefer wet plains or damp meadows near wetlands. They spend most of their time hopping through long, moist grasses hunting for food. These frogs can consume large quantities of insects, which are abundant in grasslands. They are heavily preyed upon by a number of predators, including many birds, snakes, and mammals.
Remarks: Males usually begin calling in early to late-April and sometimes continue through mid-June. I have heard them calling concurrently with Spring Peepers, Pickerel Frogs, Chorus Frogs, and in one case, Wood Frogs. Their call is a low "snore" that is very quiet and sometimes hard to hear if other, louder frogs are calling as well. In my opinion, Leopard Frogs tend to travel further from water than other frogs within WI. (almost a mile at times). In addition, they seem to be able to tolerate desiccation (loss of water) to a greater degree than many frogs that are related, such as Green Frogs. Because of this, they are commonly found in backyards and golf courses that seem nowhere near a wetland.
When threatened, Leopard Frogs are very adept at escape by making a series of zig-zagging leaps through long, thick grass. Because they are such an elusive animal, the challenge of catching a leopard Frog was one that I reveled as a child (and still do).
In my opinion, Leopard Frogs are relatively common around the La Crosse area. I have heard them calling the the La Crosse River Marsh (Myrick Park Marsh) for two consecutive years (2000 and 2001). In addition, the large number of newly metamorphosed individuals found there in the later portions of the summer lead me to believe that they enjoy a moderate survival rate. During the late summer and early fall, I have witnessed large numbers of these frogs near the La Crosse River (where it runs through the Myrick Marsh). I assume that they migrate here from the still pools of the marsh to hibernate, because the water does not freeze and remains well-oxygenated all winter. I have also seen adults in many other areas around the city of La Crosse, including; Goose Island, and several golf course ponds to name a few.
Pictured above: A "Burnsi", color morph of the Northern Leopard Frog (bottom). Burnsi morphs typically lack the dorsal spots common to the Northern Leopard Frog. This color morph is generally not seen in the La Crosse area and is more common in western Minnesota.