Other Free Encyclopedias » Animal Life Resource » Dinosaurs, Snakes, and Other Reptiles » Afro-American River Turtles: Podocnemididae - Physical Characteristics, Behavior And Reproduction, Conservation Status, South American River Turtle (podocnemis Expansa): Species Account - GEOGRAPHIC RANGE, HABITAT, DIET, AFRO-AMERICAN RIVER TURTLES AND PE

Afro-American River Turtles: Podocnemididae - Behavior And Reproduction

eggs species females nest

These turtles' behavior depends on where they live. Some of them hardly ever leave their river homes. In these species, the female often makes the only trips on land. To lay her eggs, she crawls up onto a sandbar, a ridge of sand built up by currents in the water. Besides those turtles that live only in rivers, other species live in calm pockets of water along the river, sometimes in flooded forest pools, and the females lay their eggs on riverbanks. Still other species of these turtles also make their homes in small streams and ponds, and the females make long trips over land to nest. When the dry season empties the stream or pond, they crawl underground, become inactive, and wait for the rains to return. The Madagascan big-headed turtle, for example, spends the dry season buried in the mud. Scientists know few details about the activities of the Afro-American river turtles, including whether the males "court" the females to attract them or how they mate.

THE LARGEST TURTLE EVER

Afro-American river turtles live only in South America and thousands of miles away in Madagascar, but it was not always that way. Scientists have found fossils (FAH-suhls), or the dead remains, of these turtles on every continent except Australia and Antarctica. Although the river turtles live only in freshwater rivers, ponds, and streams, the fossils show that the turtles once also lived in saltwater and on land. One of the species in this family was the largest turtle that ever lived. This turtle, known as Stupendemys geographicus, had an upper shell that measured 7.5 feet (2.3 meters) in length and might have weighed 4,000–5,000 pounds (1,814–2,268 kilograms).

Nesting time is tied to the rainy season. As the rainy season ends, the females typically start to sunbathe in the early morning and late afternoon. She then begins her migration to a nesting site, which can take a very long time. Many Afro-American river turtles nest in large groups. Each female of the group digs her own hole, where she lays and buries her eggs. The females of some species are known to use only their hind legs in digging the nest and covering up their eggs. Different species lay varying numbers of eggs in their nests. The smaller river turtles, for instance, lay about five to twenty eggs per nest, while the largest species can lay up to 156 eggs. In all species except the South American river turtle, the eggs are longer than they are wide. The South American river turtle has round eggs. Some species make one nest a year, and others make two or more. Female Madagascan big-headed turtles skip a year between nestings. Nest temperature controls the number of males and females in the nest, with very warm and sometimes particularly cold temperatures producing females, and more moderate, or mild, temperatures producing males. The eggs hatch in forty to 149 days.

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