Identification: Bullfrogs are very large, aquatic creatures typically measuring 3.5 to 8 inches in length, making them the largest frog in North America. They have an olive-brownish color (which can frange from green to yellow) with brown spots scattered over the body and webbed feet. They have large external eardrums and lack ridges on the back. Male bullfrogs have a yellow throat, whereas the female throat is white. Bullfrog tadpoles are olive-green, long tadpoles with dots on the head, body and tail. Their voice is a deep-pitched, bassy "jug-o'-rum" which can be heard over distances of a quarter mile in the forest.
Location: Bullfrogs are widely spread out over the eastern and central US, and although their limit is generally the Nebraska/Texas area, populations have been found in Colorado and New Mexico. They are abundant throughout New England.
Habitat: Bullfrogs are aquatic and can be found in almost any permanent water body, such as lakes, ponds, rivers, marshes, swamps, etc. Bullfrogs can usually be found on the bank or along the water's edge. These areas are usually well vegetated , and when the frog is startled it is just as likely to hide in vegetation as the water.
Reproduction: Bullfrogs will begin their mating call starting in late April. Eggs are laid in large numbers in "mats" that float on the water surface. Tadpoles, like the ones shown in this picture, will begin to metamorphosis in mid-June, and could take up to three years to mature.
Food: Bullfrogs will eat almost any moving prey that they can catch, and have been observed cannibalizing other newly metamorphosized bullfrogs. They are heavily preyed upon by many vertebrates, including humans (Bullfrogs are the main source of frog legs in the US). Their usual diet consists of insects, crayfish, minnows, and large frogs have even been known to catch and eat small birds and young snakes!
(above photos courtesy Al Richmond, Herpetologist, Biology Museum at UMass-Amherst)
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