page_title: Bog turtle
section_title: Life cycle
hierarchical_section_title: Bog turtle / Ecology and behavior / Life cycle
caption_attribution_description: English: A baby bog turtle in a palm
context_page_description: The bog turtle is a critically endangered species of semiaquatic turtle in the family Emydidae. The species is endemic to the eastern United States. It was first scientifically described in 1801 after an 18th-century survey of Pennsylvania. The smallest North American turtle, its carapace measures about 10 centimeters long when fully grown. Although the bog turtle is similar in appearance to the painted or spotted turtles, its closest relative is actually the somewhat larger wood turtle. The bog turtle can be found from Vermont in the north, south to Georgia, and west to Ohio. Diurnal and secretive, it spends most of its time buried in mud and – during the winter months – in hibernation. The bog turtle is omnivorous, feeding mainly on small invertebrates. The bog turtle is the state reptile of New Jersey.
  An adult bog turtle weighs 110 grams on average. Its skin and shell are typically dark brown, with a distinctive orange spot on each side of the neck. Considered threatened at the federal level, the bog turtle is protected under the United States' Endangered Species Act.
context_section_description: Bog turtles are sexually mature when they reach between 8 and 11 years of age (both sexes). They mate in the spring after emerging from hibernation, in a copulation session that usually lasts for 5–20 minutes, typically during the afternoon, and may occur on land or in the water. It begins with the male recognizing the female's sex. During the courtship ritual, the male gently bites and nudges the female's head. Younger males tend to be more aggressive during copulation, and females sometimes try to avoid an over-aggressive male. However, as the female ages, she is more likely to accept the aggressiveness of a male, and may even take the role of initiator. If the female yields, she may withdraw her front limbs and head. After the entire process is over, which usually takes about 35 minutes, male and female go separate ways. In a single season, females may mate once, twice, or not at all, and males try to mate as many times as possible. It has been suggested that it is possible for the bog turtle to hybridize with Clemmys guttata during the mating season.  However, it has not been genetically verified in wild populations.
  Nesting takes place between April and July. The female digs a cavity in a dry, sunny area of a bog, and lays her eggs in a grass tussock or on sphagnum moss. The nest is typically 3.8 to 5.1 centimeters (1.5 to 2.0 in) deep and 5 centimeters (2.0 in) around. Like most species of turtle, the bog turtle constructs its nest using its hind feet and claws. Most bog turtle eggs are laid in June. Pregnant females lay one to six eggs per clutch (mean of 3), and produce one clutch per year. A healthy female bog turtle can lay between 30 and 45 eggs in her lifetime, but many of the offspring do not survive to reach sexual maturity. Typically, older females lay more eggs than younger ones. The eggs are white, elliptical, and on average 3.4 centimeters (1.3 in) long and 1.5 centimeters (0.59 in) wide. After the eggs are laid, they are left to undergo an incubation period that lasts for 42 to 80 days. In colder climates, the eggs are incubated through the winter and hatch in the spring. The eggs are vulnerable during the incubation period, and often fall prey to mammals and birds. In addition, eggs may be jeopardized by flooding, frost, or various developmental problems. It is unknown how gender is determined in bog turtles.
  Baby bog turtles are about 2.5 centimeters (0.98 in) long when they emerge from their eggs, usually in late August or September. Females are slightly smaller at birth, and tend to grow more slowly than males. Both genders grow rapidly until they reach maturity. Juveniles almost double in size in their first four years, but do not become fully grown until five or six years old.
  The bog turtle spends its life almost exclusively in the wetland where it hatched. In its natural environment, it has a maximum lifespan of perhaps 50 years or more, and the average lifespan is 20–30 years. The Bronx Zoo houses several turtles 35 years old or more, the oldest known bog turtles. The zoo's collection has successfully sustained itself for more than 35 years. The age of a bog turtle is determined by counting the number of rings in a scute, minus the first one (which develops before birth).
caption: A baby bog turtle held in a palm
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