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.