Clawed Frogs and Surinam Toads: Pipidae

Physical characteristics: The common plantanna goes by several different common names, including African clawed frog and clawed toad. It has a flat head and body with long and strong hind legs. Its back and the top of its head are dark-colored, usually gray to olive-brown and sometimes are marked with dark, occasionally orangish, spots. Its underside is lighter colored and may be off-white, light gray, or grayish yellow, sometimes with faint, gray speckles. A thin row of what look like stitches run down each side of the otherwise smooth back from behind the eye to the rump. Each row holds 23 to 31 "stitches." The plantanna has two tiny eyes on top of its wide head and a tiny bit of flesh, called a tentacle, under each eye. It has no The common plantanna is a water-loving species. It can live in all types of water from fast-moving rivers to calm ponds. (Photograph by E.R. Degginger. Bruce Coleman Inc. Reproduced by permission.) tongue. True to its name, it has little black claws on three toes of each hind foot. The feet are quite large and have gray webbing between and to the tips of the long toes. Sometimes the webbing has a little yellow or orange color to it.

Males and females of this slippery-bodied frog look nearly alike, except that males are smaller. A male grows to about 1.8 to 3.8 inches (4.6 to 9.7 centimeters) long from the tip of the snout to the end of the rump, while females can reach 2.2 to 5.8 inches (5.6 to 14.7 centimeters) long.

Geographic range: The common plantanna is an African frog that lives as far south as South Africa and north to Kenya, Uganda, the Democratic Republic of Congo, and Cameroon. In addition, people have introduced them to many other nations, including England, Germany, Chile, and the United States.

Habitat: The common plantanna is a water-loving species. It can live in all types of water from fast-moving rivers to calm ponds. It can even survive in mucky pools and swamps and in somewhat salty water. Although its native African habitats do not cool much in the winter, it has held up well in places that have winters cold enough to freeze the tops of ponds.

Diet: Tadpoles eat by straining little pieces of algae (AL-jee) and other tidbits from the water. Algae are tiny plantlike organisms that live in water but have no true roots, stems, or leaves. Once the tadpoles change into froglets, their diet switches to insects and other invertebrates they find in the water. Adults also eat young, or larval (LAR-vuhl), mosquitoes and other insects, sometimes leaping out of the water to nab a flying insect, and will eat larger things, such as fish or birds and mammals that fall into the water. Sometimes they even eat their own eggs and tadpoles.

Behavior and reproduction: Common plantannas stay in the water for almost their entire lives, only coming onto land now and then at night. People most often see them floating at the water's surface, with legs outstretched, and only the top of their heads out of the water. If their pond or swamp dries up, they will dig down into the mud, hind end first, and bury themselves until the rains return.

In addition to signaling the end of estivation for some frogs, the rains combine with warm weather to trigger the mating season for the entire species. Unlike most other types of frogs, both the males and the females call. Their call, which they make underwater, sounds like a buzzing tap. The females lay about one thousand tiny tan eggs, which stick to underwater plants and rocks.

Common plantannas and people: Though it seems strange now, until the 1940s, people turned to these frogs to learn whether a woman was pregnant. To do it, they used a hypodermic needle to suck up a little of the woman's urine and then inject it under the skin of the female frog. If the woman was pregnant, the hormones in her urine would spark the frog to start laying eggs. If the woman was not pregnant, the frogs laid no eggs. Medical professionals now find out if a woman is pregnant through other tests that do not involve frogs.

Nowadays, this species has another role in medicine. One chemical in its skin kills bacteria and may be a useful antibiotic, while another may be helpful in explaining how the human brain works. Besides its importance in medicine, people buy and sell the common plantanna as a pet. Some local people in Africa also once collected the frogs for food.

Conservation status: Because these frogs live in many areas and do well in a variety of different habitats, the species is not considered to be at risk. ∎