Eurasian Pond and River Turtles and Neotropical Wood Turtles: Geoemydidae
EURASIAN POND AND RIVER TURTLES AND NEOTROPICAL WOOD TURTLES: GeoemydidaeYELLOW-MARGINED BOX TURTLE (Cistoclemmys flavomarginata): SPECIES ACCOUNT
Eurasian pond and river turtles and neotropical wood turtles are small to large turtles. The upper shell, or carapace (KARE-a-pays), is bony. Most of these turtles have webbing between their toes. Some of them have a side-to-side hinge in the bottom shell, or plastron (PLAS-trun), which allows them to close up tight if they feel threatened. In some species, the males and females look quite different from each other. The male Indian tent turtle, for example, grows to only about a third of the size of the female, which is typically 1 foot (30.5 centimeters) long. The largest members of this family weigh 110 pounds (50 kilograms) and have upper shells that can reach 32 inches (81 centimeters) in length.
These turtles live in Eurasia, North Africa, Mexico, and Central and South America.
The members of this family live in the saltwater of the ocean's coastline, in inland freshwater areas, or on land in forests. They typically are found in the tropical areas of many countries, including China and the nations of the East Indies and Europe. They live from northern Mexico in North America to Ecuador and Brazil in South America. They also live in regions bordering the tropics, which are called "subtropical" regions.
Some Eurasian pond and river turtles and neotropical wood turtles eat only meat, and some eat only plants; others will dine on both meat and plants. In one species, called the Chinese stripe-necked turtle, the juveniles (JOO-vuh-nuhls), or young turtles, and the males eat mainly meat in the form of insects, but the females are primarily vegetarians and eat mostly leaves, seeds, and roots from the shoreline plants.
BEHAVIOR AND REPRODUCTION
Just as the habitat, or the natural living area, differs from species to species in this family, so, too, does their behavior and method of reproduction. Some of them hardly ever leave the water, but others live on land. Many of them are active all year long, but others become inactive during the winter months or during dry spells. Some, such as the Chinese stripe-necked turtle, sunbathe, or "bask," onshore to warm their bodies.
Although scientists know few details about many of these turtles, they have noted that the adult male of some species will bite or bump up against a female to persuade her to mate. Also, the heads and legs of a few species will become more brightly colored during mating season, probably to attract a mate. Male painted terrapins, for example, normally have gray heads, but their heads become white with a red stripe during mating season.
Females of the larger species lay the most eggs—up to thirty-five eggs at a time. The smallest species may lay just a single egg. Female painted terrapins travel as far as 31 miles (50 kilometers) to reach a good nesting site and then lay their eggs at night. They lay eggs about five times a year. In many cases, the temperature of the nest does not affect the sex of the newly hatched young turtles. In other species, however, a particularly warm nest temperature produces all females, and a cool one produces males. In at least one species, the eggs may also become females if the nest temperature is especially cold.
Eggs hatch in sixty to 272 days. In some species, males can become parents when they reach three or four years old, but females must wait until they are five to eight years old. Sometimes two different species of Eurasian pond and river turtles and neotropical wood turtles mate with each other and produce young turtles. This can happen often when two turtles from different species of this family are put together in one aquarium, but it may not happen as often in the wild.
EURASIAN POND AND RIVER TURTLES AND NEOTROPICAL WOOD TURTLES AND PEOPLE
Some people who live near these turtles collect them to eat their meat or to use them in making medicines. They are also popular in the pet trade. The painted terrapin, for example, is especially popular, because some people believe that this turtle brings good luck.
According to the World Conservation Union (IUCN) eleven species are Vulnerable, meaning that there is a high risk that they will become extinct in the wild. Eighteen species are Endangered, or facing a very high risk of extinction, and thirteen are Critically Endangered, or facing an extremely high risk of extinction. One species is Extinct; there is no longer any living turtle in the species. The U.S. Fish and Wildlife Service describes the Indian sawback turtle and river terrapin as Endangered. Turtle declines can be traced to too much collecting and to loss of their habitat. Efforts are under way to breed some of the most threatened species in captivity to increase their numbers.
Physical characteristics: The yellow-margined box turtle has a bright yellow stripe down its upper shell and another yellow stripe that runs from behind the eye onto the neck. The upper shell is arched and rounded, and the lower shell is large, with a side-to-side hinge that allows the turtle to tightly close it. In this small turtle, the upper shell measures just 7 inches (17.8 centimeters) in length.
Geographic range: This turtle is found in China, Taiwan, and the Ryukyu Islands of Japan.
Habitat: Yellow-margined box turtles mainly live in the warm-weather forests of southern China, Taiwan, and the Ryukyu Islands. They sometimes travel into rice paddies and freshwater ponds and streams. Some of them only rarely, if ever, leave the forests.
Diet: Some members of this turtle group eat only plants, some eat only meat, and others eat both plants and meat.
Behavior and reproduction: Since they live on land, the yellow-margined box turtles must be able to defend themselves against animals that might attack and kill them. These predators (PREH-duhters) can easily outrun them, but they can protect themselves by tucking in their heads, legs, and tails and then using the hinges on their lower shells to seal shut the shells and keep the predators from reaching their soft flesh. If the weather turns particularly hot, the turtles may also hide inside the sealed shell so they do not dry out. When the cooler winter months arrive, the turtles bury themselves under leaves or hide under a log or inside another animal's underground burrow and wait for warmer weather.
During mating season, the male runs at and bumps against the female to encourage her to mate with him. Depending on where she lives, the female may nest from May or June through July, August, or September. Some nest only every other year, but they may make one to three nests in a single season. The female picks a spot in an open area at the edge of a forest, digs a shallow hole, and lays one to four eggs, ranging in length from 1.6 to 2.1 inches (40–53 millimeters) and in width from 0.9 to 1.1 inches (23–28 millimeters). An egg can weigh 0.4–1.0 ounces (11.3–28.3 grams). The eggs hatch in about two months. The young cannot mate until they are twelve to thirteen years old.
Yellow-margined box turtles and people: Many local people eat this turtle or collect and kill it to make medicines. It is also popular in the pet trade.
Conservation status: According to the World Conservation Union, this species is Endangered. Threats to its survival include too much collection and the destruction of the forests where it lives. ∎
FOR MORE INFORMATION
Burnie, David, and Don E. Wilson, eds. Animal: The Definitive Visual Guide to the World's Wildlife. London: Dorling Kindersley, 2001.
Liat, Lim Boo, and Indraneil Das. Turtles of Borneo and Peninsular Malaysia. Kota Kinabalu, Malaysia: Natural History Publications (Borneo), 1999.
Zhou, J., and T. Zhou. Chinese Chelonians Illustrated. Nanjing, China: Jiangsu Science and Technology Publishing House, 1992.