Bronze Frog (Rana clamitans clamitans)
- Other Names
- Banjo Frog
- The bronze frog grows up to 2 to 4 inches (5.4 to10.2 cm). Distinguishing characteristics include a bronze to brownish body, white belly with dark, irregular blotches, and a bright green upper lip and nose. Males may have yellowish throats. Bronze frogs are smooth skinned, like all true frogs. They have long hind legs with webbed toes. A fold of skin, called a lateral line, begins behind the eye and runs two-thirds the length of body. The tympanum (ear disc) is larger in males.
- Life History
Named for its body color, the bronze frog is a secretive species, hiding under vegetation near ponds, creeks and rivers. It may be difficult to find until warm, humid evenings when its mating call is heard. Their diet includes small frogs, worms, insects, and other small invertebrates. Birds, fish, and small carnivores (meat eaters) prey on the bronze frog.
It reaches sexual maturity in the first full summer after metamorphosis. Breeding season begins in early spring and lasts through the summer. Females lay 2,000 to 4,000 eggs in small masses attached to underwater vegetation. Eggs are 1.5 mm when laid, but grow to 6 mm as cells divide. Incubation is 1 to 2 weeks. Tadpoles are green with small, dark spots. They grow 1 to 1.5 inches (28 to 33 mm) before they metamorphose (change from tadpoles to frogs). Bronze frogs live 7 to 10 years.
Bronze frogs are nocturnal and solitary. They remain under cover, in logs and crevices, most of the time. Male bronze frogs court females with a distinct call. Researchers agree that the love song of the bronze frog sounds like someone plucking a loose banjo string. In fact, another common name for the bronze frog is the "banjo frog."
Rana is the Latin word for "frog." Clamitans, the species and subspecies name, means "noisy" and refers to the call of the male. The bronze frog is a member of the true frog family, the Ranidae family. The moist, permeable skin of the bronze frog (like other frog species) makes it very sensitive to pollution, a good indicator of water quality for people.
- Bronze frogs prefer shallow streams, ponds, marshes, springs, and swamps with plenty of vegetation.
- Bronze frogs are found in the southeastern portion of the United States, from North Carolina to the eastern third of Texas.
- There is concern about the decline in amphibian populations worldwide, although there is not enough information about most amphibians (bronze frogs included) in Texas to determine whether there is cause for concern here. Worldwide, scientists are investigating a number of possible causes for amphibian decline: acid rain, herbicides, insecticides, fertilizers, industrial waste, habitat destruction, introduced species, bacteria, ozone depletion and global warming. It could be a combination of any or several of these suspected causes. In Texas, citizens can join Texas Amphibian Watch to help scientists keep an eye on the health of Texas amphibian populations. To join, call 512-912-7011