Leopard Frog

leopard frogFew creatures have the patience and superior ambushing skills of the leopard – the leopard frog that is.

Leopard frogs are the familiar frogs used in biological studies and are considered true frogs. Like all true frogs, leopard frogs have smooth, moist skin and a ridge on each side of the body that runs from the eye to the hind legs, separating the back from the sides. All leopard frogs are either brown or green or a combination of those two colors. They have a long, pointed head, round, dark spots, and a distinct light spot on the tympanum or eardrum. Leopard frogs are easily mistaken for pickerel frogs, which are similar in appearance but have rectangular or square spots.

Oklahoma has three species of leopard frogs, though only two are native. The southern leopard frog (Rana utricularia) is most abundant in the eastern half of the state with some individuals venturing into southwest Oklahoma. The plains leopard frog (Rana blairi) can be seen throughout Oklahoma except in the southeastern counties. The northern leopard frog (Rana pipiens) is native to North America, but has been introduced into Oklahoma in several parts of the state. All three leopard frogs are similar in general appearance and living habits.
Ideal habitat for the leopard frog consists of shallow, freshwater habitats in open or lightly wooded areas. This wetland habitat is essential for frog survival, and the loss of wetlands since 1900 has greatly affected leopard frog populations not only in Oklahoma, but nationwide. Meadow or grass frogs, as they are sometimes called, are regularly seen some distance from water. They frequently search for prey in grassy fields and are common lawn and garden visitors during the summer. Leopard frogs spend the day hiding among the tall grass and emerge toward evening to feed. During the winter, they hibernate at the bottoms of ponds or streams.

After a long hibernation, adult leopard frogs quickly turn their attention to breeding. During early spring and summer, as well as fall and winter for the southern leopard frog, males fill the air with sweet, deep rattling snores followed by several clucking grunts to attract females. They breed in both permanent and temporary streams, pools, ponds or ditches and attach the large jelly-like cluster of eggs to vegetation or rocks beneath the water surface. Females lay 3,000 to 6,000 eggs that hatch in about 10 days.

Like all amphibians, leopard frogs experience a double life. As tadpoles, leopard frogs have gills and a streamlined body with a long flattened tail they use for propulsion. After four months, the tadpoles undergo a remarkable change. The gills become lungs, the eyes migrate to the front of the head, the tail disappears, legs arise, and the mouth widens into a characteristic froggy grin. During this time, their diet and digestive system change as well.

As tadpoles, they are herbivores, grazing on the tips of plants and on algae floating on the water or attached to a rock or water-plant. Mature frogs are carnivores that eat anything they can catch. Insects, including beetles and grasshoppers, are their most common prey, but they’ll take crayfish, small mammals and fish, and even young leopard frogs if the opportunities arise.

The next time you encounter a leopard frog and notice its wide grin, it’s probably still smiling from its last long-awaited meal.