Like many cold-blooded reptiles, the bog turtle is active only during the warmer parts of the day. It emerges from its night-time shelter and basks for some time in the sun before commencing its search for food (2). This semi-aquatic turtle forages both on land and underwater (2). Its highly varied and omnivorous diet consists primarily of insects, such as beetles, millipedes, dragonflies, and ants, but it also feeds on snails, slugs, earthworms and spiders (5), and even frogs, nestling birds, mice and voles. Berries, seeds, and other plant parts comprise the vegetarian part of its diet (2).
Mating takes place from March until June, and begins with a male searching out a female, identifying her sex by using sight and smell. Whilst circling the female, the male probes her tail and cloacal area with his nose, and may bite at her head and neck. The female may move away, resulting in a chase, with the male biting at her legs and head to stop her. Finally, the male will mount the female, accompanied by more bites to the head and neck, and mating lasts for 5 to 20 minutes (2).
The bog turtle lays eggs in June and July (2), usually in the late afternoon or early evening (5). The single clutch of one to six white eggs are laid either into a cavity dug by the female, or under moss or grass tussocks (2). The eggs hatch in August or September, and while most hatchlings emerge from the nest immediately, some may remain in the nest over winter (2). Both the eggs and hatchlings are preyed upon by a number of birds and mammals, including foxes, raccoons, and opossum (4).
In October (4), the bog turtle retreats into areas of dense vegetation to hibernate (5). Resting in soft mud, often just below a frozen surface, in the old burrow of a muskrat or meadow vole, amongst rocks, roots or under vegetation (5), the bog turtle will remain in hibernation until April (4). As well as burrowing for hibernation, this proficient digger will quickly burrow into the muddy ground whenever it is alarmed (2).