Green frog
Rana clamitans melanota

Fig. 26. Green frog

The green frog is certainly one of the most common and widely distributed frogs in Ohio. It is in many ways similar to a small bullfrog, reaching 70-90 mm in length, but it has two dorsolateral folds extending back from the tympanum two-thirds the distance to the hind legs (Fig. 26). Color varies from olive brown through shades of green with small dark spots on the sides and back. Green frogs are often seen with a greenish head but with an olive brown body. Regardless of the body and head color, there is nearly always a green facial mask before the eyes. Males have paired vocal sacs, a yellowish wash on the throat, and a tympanum larger than the diameter of the eye. The throat of adult females is bright white, and the tympanum and eye are equal in size.

The decidedly aquatic green frog requires permanent ponds, lakes, or streams. During wet periods they frequently travel overland to new areas. Green frogs are habitat generalists and are found in more habitat types and in association with more species of amphibians than any other Ohio frog.

• The green frog is similar to a small bullfrog except that it has dorsolateral ridges coursing from the tympanum two-thirds the distance to the hind legs.

• Color varies from olive brown through shades of green with small dark spots on the back and sides.

• The throat of the adult male has a yellow wash, whereas that of immature males and females is white. In addition, the tympanum is larger than the eye in adult males but about the same size as the eye in females.

Green frogs, like most members of their family in Ohio, hibernate on the bottom of ponds and streams. They are active from mid-March through late October or even into December. Territorial males begin calling from potential breeding sites in late April or early May and continue into mid-July. The advertisement call is a low pitched grunt not unlike the plunk of a loose banjo string or the "k-tung" of a snapped thick rubber band (Fig. 27); it has little carrying power. When startled on shore, green frogs frequently emit a single squawk as they vault through the air toward the water.

	Fig. 27. Call of the green frog

Call of the green frog (51 seconds, 401 KB)
Excerpt (14 seconds, 113 KB)

• The call of the green frog is a low pitched grunt, not unlike the plunk of a loose banjo string or the "k-tung" of a snapped thick rubber band.

• The dominant frequency of the call illustrated is 1700 Hz, and the call duration is 0.06 seconds.

• Background choruses of green frogs, a lone spring peeper, a distant common gray treefrog, and bullfrogs produced the background "noise" present in the spectrogram and in the audio clip.

Fig. 25. Tadpole of the green frog

Eggs are laid from early May through July in a floating mass or film at the surface. The 4000 eggs laid by each female average 1.5 mm when freshly laid but increase to 6 mm in diameter when the two envelopes swell. Eggs are laid in warm water and hatch in three to six days. Tadpoles may spend one winter in the pond and then transform into small frogs 28-33 mm in length (Fig. 25), or if they are young from an early clutch, they may metamorphose that same year. Green frogs may survive seven to ten years in the wild.

• Green frog tadpoles are olive on the back and sides. The body, tail musculature, and tail crest are dotted with dark spots with indistinct margins that fade into the ground color.

• The green frog tadpole may transform the same year as hatched from the egg, or it may overwinter as a tadpole for one winter.

• Tadpoles reach lengths of 28-33 mm before undergoing transformation.