Leopard Frog
Few
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.