True Frogs: Ranidae

Physical characteristics: True to its name, the goliath frog is huge. It is the largest frog living on Earth today. An adult can reach a whopping 12.6 inches (32 centimeters) long from snout to rump. One frog can weigh 7 pounds (3.25 kilograms). The frog has a wide, flattened body that blends into its also-wide head without a noticeable neck. Its head is shaped like a triangle with a blunt point at the end of the snout. The frog's back, head, and the upper surface of all four legs are dark gray, sometimes a bit brownish or greenish, and covered with tiny bumps. Faint dark bars and/or spots sometimes show on the legs and lips. The underside is a lighter color, often appearing a greenish The goliath frog is at home in rapids and other fast-moving parts of rivers. (Photograph by Paul A. Zahl. Photo Researchers, Inc.) tan. The hind legs are long. The front legs are shorter, but thick. The toes on the front feet have a bit of webbing at their base but not out to the ends. The hind toes have full webbing all the way to their tips.

Geographic range: It lives in a small part of west-central Africa from southern Cameroon to parts of Guinea.

Habitat: The goliath frog is at home in rapids and other fast-moving parts of rivers.

Diet: Scientists are not sure what it eats. Given its enormous size, many types of food are possible.

Behavior and reproduction: Scientists know little about this frog's behavior outside of the breeding season. At that time, the males begin calling, but they do it in a way that is different than most other frogs. Most male frogs suck air into vocal sacs and blow it out to make their calls. The goliath frog and other closely related species have no vocal sacs and instead hold the mouth barely open and make a long whistling noise. Females follow the whistling to the males. One female can lay several hundred eggs at a time. Each egg is very small, about 0.14 inches (3.5 millimeters) in diameter, and sticks to plants growing in rocky areas of the river rapids. The eggs hatch into tadpoles, which can grow to 1.9 inches (4.7 centimeters) long over the next eighty-five to ninety-five days. They then turn into froglets.

Goliath frogs and people: Local people often hunt this frog for food by searching for it from boats and using a gun to shoot at it. Once they have wounded or killed it, the hunters leap into the water to snatch up the frog. New traps for capturing the frogs are making the hunters even more successful. The hunters may either eat the frogs themselves or sell them to markets. Some people also capture goliath frogs alive to sell in the pet trade, to zoos, or to people who hold frog races.

Conservation status: According to the IUCN, this species is Endangered, which means that it faces a very high risk of extinction in the wild. In the fifteen-year period from 1989 to 2004, the number of goliath frogs dropped by more than half. Hunting them for meat and collecting them for the pet trade are the main reasons for the fall in numbers. In addition, the frog's forests are also disappearing as people cut down trees, farm the land, and construct buildings. These activities are also allowing soil to run downhill and muddy up the streams where the frog breeds, and this may hurt the tadpoles. Some people believe that ecologists should begin breeding the frogs in captivity to make sure the species survives into the future. ∎