The Wood turtle (Glyptemys insculpta) is a semi-aquatic species of turtle endemic to North America. It spends a great deal of time in or near the water of wide rivers and spends the winter in hibernation and the hottest parts of the summer in estivation. On an average day, a Wood turtle will move 108 meters (354 ft), a decidedly long distance for a turtle. When unharmed, it can live for up to 40 years in the wild and 58 years in captivity.
Wood turtles have a rough carapace that is a tan, grayish brown, or brown color, with a central ridge (called a keel) made up of a pyramidal pattern of ridges and grooves. Older turtles typically display an abraded or worn carapace. The larger scutes display a pattern of black or yellow lines. The Wood turtle's plastron (ventral shell) is yellowish in color and has dark patches. The posterior margin of the plastron terminates in a V-shaped notch. Although sometimes speckled with yellowish spots, the upper surface of the head is often a dark gray to solid black. The ventral surfaces of the neck, chin, and legs are orange to red with faint yellow stripes along the lower jaw of some individuals. Seasonal variation in color vibrancy is known to occur. At maturity, males are larger than females. Males also have larger claws, a larger head, a concave plastron, a more dome-like carapace, and longer tails than females. The plastron of females and juveniles is flat while in males it gains concavity with age. The posterior marginal scutes of females and juveniles (of either sex) radiate outward more than in mature males. The coloration on the neck, chin, and inner legs is more vibrant in males than in females who display a pale yellowish color in those areas. The plastrons of hatchlings are dull gray to brown. Their tail usually equals the length of the carapace and their neck and legs lack the bright coloration found in adults. Hatchlings' carapaces also are as wide as they are long and lack the pyramidal pattern found in older turtles.
Wood turtles occur in a broad geographic range extending from Nova Scotia in the north (and east) to Minnesota in the west and Virginia in the south. In the past, it was forced south by encroaching glaciers: skeletal remains have been found as far south as Georgia. These turtles prefer slow-moving streams containing a sandy bottom and heavily vegetated banks. The soft bottoms and muddy shores of these streams are ideal for overwintering. Also, the areas bordering the streams (usually with open canopies) are used for nesting. In spring and summer Wood turtles occur in open areas including forests, fields, bogs, wet meadows, and beaver ponds. The rest of the year is spent in the aforementioned waterways.
Wood turtles are diurnal creatures. During the spring, they are active during the daytime and will almost always be found within several hundred meters of a stream. The early morning and late afternoon are preferred foraging periods. Throughout this season, Wood turtles use logs, sandy shores, or banks to bask in the sunlight. During the summer, Wood turtles are considered largely terrestrial animals. At night they will rest in small creeks or nearby land (usually in areas containing some sort of underbrush or grass). During warmer weather, Wood turtles stay in the water for a larger percentage of the time. For this reason, during the winter months (and the late fall and early spring) they are considered aquatic turtles. November through February or March is spent in hibernation at the bottom of a small, flowing river. Wood turtles are generally solitary but may hibernate alone or in large groups. During this period, they bury themselves in the thick mud at the bottom of the river and rarely move. Although being solitary species, male Wood turtles establish dominance hierarchies and can be aggressive, with larger and older turtles being more dominant. Larger males rank higher on the social hierarchy often created by wood turtle colonies.
Wood turtles are omnivorous, feeding mainly on plant matter and animals both on land and in water. They eat beetles, millipedes, and slugs. Wood turtles also consume specific fungi, mosses, grasses, various insects, and also carrion.
Mating activity among Wood turtles peaks in the spring and again in the fall, although they may breed throughout the portion of the year they are active. Males fight to gain access to females. The courtship ritual consists of several hours of 'dancing,' which usually occurs on the edge of a small stream. Males often initiate this behavior: starting by nudging the female's shell, head, tail, and legs. Because of this behavior, the female may flee from the area, in which case the male will follow. Nesting occurs from May until July. Nesting areas receive ample sunlight, contain soft soil, are free from flooding, and are devoid of rocks and disruptively large vegetation. Females may also travel long distances in search of a suitable site, sometimes a 250 meters (820 ft) trip. Before laying her eggs, the female may prepare several false nests. After a proper area is found, she will dig out a small cavity, lay about 7 eggs (but 3 to 20 is common), and fill in the area with earth. Females in general lay one clutch per year. Incubation lasts 47-69 days. Hatchlings emerge from the nest between August and October and are independent at birth. They become reproductively mature between 14 and 18 years of age.
Despite many sightings and seemingly large and diverse distribution, Wood turtle numbers are in decline. A large number of deaths caused by humans result from habitat destruction, farming accidents, and road traffic. Also, these turtles are commonly collected illegally for the international pet trade.
The IUCN Red List and other sources don’t provide the number of the Wood turtle total population size. Currently, this species is classified as Endangered (EN) on the IUCN Red List and its numbers today are decreasing.