The river frog has no dorsolateral ridges as found in many other ranid frogs. Tadpoles of the river frog are rather large, reaching 4 inches before metamorphosis. The tadpoles undergo ontogenetic color changes. Reproduction Male river frogs call to attract local females from April into July. The call of larger more mature frogs is a deep, low pitched, roaring snore.
Smaller males give off a much higher pitched call than do the larger males.
When the male attracts a female they will go into amplexus. The female will lay several thousand eggs that form into a surface film, often among emergent vegetation to which they adhere. Behavior The river frog is a highly aquatic frog, but can be approached rather easily. Habitat The river frog is not limited to rivers as its name may imply. They can also be found in and along lakes, ponds, swamps, streams, and marshes.