The Yellow-spotted Amazon turtle, Podocnemis unifilis, grows to a length of 12 to 17 1/2 inches. The carapace (upper shell) is dark brown to black, and has a distinct keel (prominent ridge) on the second and third vertebral scutes. The front legs have five claws and the hind legs are webbed with four claws. The head is dominated by paired frontal scales, which meet along a distinct groove between the eyes.

Turtles of this genus have two or three barbels (an elongated sensory projection) under the chin. The Yellow-spotted Amazon has only one, hence the name unifilis.

Juveniles have greenish irises and black heads spotted with bright yellow. Adult females have grayish skin, black irises, and they lose most of their yellow head spots. Their carapace is dark brown, often with a dark median streak. Adult males are smaller than females. They retain their yellow head spots, have a longer thicker tail, grayish skin, and greenish irises.

Yellow-spotted amazons are found in Northern South America, Venezuela and Surinam to northern Brazil; mainly in Amazon and Orinoco river drainages, in large rivers, backwaters, lagoons, and flooded forests. They usually inhabit rivers only during mating season. At other times they live in lagoons and backwaters.

These turtles are herbivorous, feeding on aquatic vegetation and fruits of waterside plants. They open their mouths at the water surface filling it with fine particulate surface food. Then it closes its mouth, filtering water through its nostrils and jaw.

Females congregate on and near the beach during the nesting season for several days to bask. Males also congregate, but do not usually bask.

A relatively shallow nest, 6-10 inches, is dug in a variety of substrates, preferably on sandy beaches. 14 to 49 elongated, hard-shelled eggs are laid, approximately 1-3/4 x 1-1/4 inches. The nest is filled, then stamped flat with an open foot and loosely swept over. Two clutches may be laid per season.

Incubation is 75 to 90 days, averaging 84. The shell is first ruptured at approximately 64 days. The young remain in the shell several days until the yolk sac is completely absorbed. They gather at the top of the nest chamber and emerge after another two weeks, at night and usually after rain.