African Treefrogs: Hyperoliidae

African treefrogs are also known as reed and sedge frogs. The typical African treefrog has a slender body, large and often bulging eyes usually with horizontal pupils, and rounded pads on the ends of its webbed toes. Its back legs are long and thin, and its front legs are also quite thin. The treefrogs with this appearance are good climbers and leapers. Some of the African treefrogs look quite different. These species, which are often called running frogs, remain on the ground; have no toe pads or toe webbing; have shorter hind legs, frequently only a bit longer than the front pair; and walk or run rather than hop.

The males of this family have large vocal sacs, which are pouches in the throat area that blow up and then deflate when they call. Male African treefrogs have a vocal sac, which may blow up to be three or more times as big as the head. In many species, this sac is covered with an oval-shaped flap that can be seen even when the frog is not calling.

The African treefrogs come in many different colors and patterns. In some cases, even members of the same species do not look alike. One member of the species known as the painted reed frog, for example, may be green with a few dozen, tiny, black-centered, yellow spots on its back, orange toes, and orange upper legs. Another might be greenish gray with large black blotches, tan with black and yellow markings on its sides, or cream with black and orange stripes. The following examples will show the varying colors among different species within this family:

• Greater leaf-folding frog, also known as the spiny leaf-folding frog—Chocolate brown with a wide silvery to light brown back, which is sometimes split down the middle with a chocolate brown stripe; also with silvery to light brown color on the top of the hind legs
• Yellow-striped reed frog—Light green with a yellow stripe on each side of its body from the snout over the large, orange-colored eye to the rump; orange toes and a yellow underside with orange on its rear legs
• Yellow-legged kassina, also known as the yellow-legged treefrog—Beige with many brown spots on its back, brown bands on its legs and toes, and yellow on the underside of upper rear leg
• White-spotted reed frog—White, covered with small yellow dots that are outlined in dark brown
• Transparent reed frog, also known as the water lily reed frog— Light green with orange toes
• Malagasy variable reed frog—Orange yellow with small brown spots on the head and front half of the back and a narrow brown stripe on each side of the snout
• Madagascar reed frog, also known as the blue-back frog—Baby blue head and back, orange yellow underside, dark orange toes, two black stripes from the snout to the eyes, and a few black spots on both sides between the eye and the front leg and on the front leg

Depending on the species, African treefrogs may have eyes that are all brown, gold, whitish, or some other solid color, or that are one color on the top half and another on the bottom half. The Malagasy variable reed frog, for instance, has large eyes that are white on the bottom and pinkish on the top. Most of the treefrogs have large eyes, but in some species they are enormous. The Seychelles treefrog is an example. Its pearly white eyes look almost like big headlights.

Often the color of the frog changes as it grows older. Young froglets in many species are yellow or brown with dark markings down the back, while the adults are brightly colored and patterned. In some species, the youngsters are green, while the adults are brownish. Scientists call these colors the "juvenile phase." Sometimes, many of the adult males have the juvenile colors during the breeding season, too.

Adult African treefrogs may be as small as 0.5 inches (1.2 centimeters) long from the tip of the snout to the end of the rump or as large as 4.3 inches (11.0 centimeters) in length. While males and females are the same size in many species, the females are larger in others. The African wart frog and the greater leaf-folding frog are two species in which the males and females reach the same size. Adult African wart frogs grow to 1.4 inches (3.6 centimeters) long, and adult greater leaf-folding frogs reach 1.6 inches (4.1 centimeters) in length. Female toad-like treefrogs, on the other hand, are larger than males. In this species, females grow to 1.4 to 1.6 inches (3.6 to 4.1 centimeters), while males reach only 1.1 to 1.3 inches (2.9 to 3.3 centimeters) in length. The difference between the sexes is even more noticeable in the big-eared forest treefrogs. Here, females reach up to 3.3 inches (8.4 centimeters) long, while males are about half that size at 1.6 to 1.8 inches (4.1 to 4.6 centimeters) in length.