Narrow-Mouthed Frogs: Microhylidae

With 362 species, this large family of narrow-mouthed frogs comes in many shapes and sizes. Most species are brown, tan, or yellow-brown on their backs, sometimes with brighter colors on their undersides. The horned land frog, for example, has a brown back and gray sides, but may have an orange or red underside. The saffron-bellied frog has a black back with yellowish to silvery flecks, and large, bright yellow spots on its black sides and belly. Some, like the rubber frog, stand out even more. The rubber frog has a dark brown to black body with pink or red markings on its back.

Many, but not all, of the narrow-mouthed frog species have a round, wide, often chubby-looking body and a short head that ends in a narrow or pointed snout. This gives these species an overall shape that resembles a pear or a teardrop. Others do not have this body shape. Some are long and thin, and others have rounded bodies with fairly wide heads. The New Guinea bush frog, for example, has a head that is just as wide as its body. Rain frogs of the genus Breviceps are also plump and round. They have such tiny legs that they cannot hop, and walk instead. Another rather plump frog, known as the ornate narrow-mouthed frog, has longer legs than Breviceps and is an excellent hopper.

Many, but not all, of the narrow-mouthed frogs have noticeable, small warts on their backs and legs. The typical member of this family has little or no webbing on its toes. Many have pads on their toe tips. The horned land frog, for instance, has large pads, especially on the toes of its front legs. The eyes of species in this family are frequently small, but some, like Boulenger's callulops frog, have large eyes. A few, including the New Guinea bush frog and the horned land frog, have eyelids decorated with small spines that almost look like thick eyelashes.

The majority of the frogs in this family share a few somewhat hidden characteristics. Unlike other frogs, most species of narrow-mouthed frogs have two or three zigzag folds on the roof of the mouth. The roof of the mouth is called the palate (PAL-ett). The majority of the species in this family also have no teeth. In addition, most narrow-mouthed frogs have smaller bones in the shoulder and chest than other frogs typically have. Some, like the Malaysian painted frog, have no neck bones and, therefore, no neck. In this case, the head almost blends in with the body, which makes the frog look quite chubby. In fact, the nickname of the Malaysian painted frog is chubby frog.

The typical narrow-mouthed frog grows to 1.6 inches (4 centimeters) long from snout to rump, and some never even reach 0.5 inches (1.3 centimeters) long as adults. The largest species, like the Malaysian painted frog, can top 3 inches (7.5 centimeters) long, and some can reach 4 inches (10 centimeters) in length. In most species of narrow-mouthed frogs, females are at least a little larger than the males. In some cases, like Bushveld's rain frog, the female is almost twice the size of the male.