Considered threatened at the federal level, the bog turtle is protected under the United States' Endangered Species Act.
Demand for the bog turtle is high in the black market pet trade, partly because of its small size and unique characteristics.
Muhlenberg, who named more than 150 North American plant species, was conducting a survey of the flora of Lancaster County, Pennsylvania, when he discovered the small turtle.
[10] Synonyms include Emys biguttata, named in 1824 by Thomas Say on the basis of a turtle from the vicinity of Philadelphia, and Clemmys nuchalis, described by Dunn in 1917 from near Linville, North Carolina.
[25] The bog turtle is native only to the eastern United States,[nb 1] congregating in colonies that often consist of fewer than 20 individuals.
[28] They prefer calcareous wetlands (areas containing lime), including meadows, bogs, marshes, and spring seeps, that have both wet and dry regions.
[15] The bog turtles' preferred habitat, sometimes called a fen, is slightly acidic with a high water table year-round.
[23] Rushes, tussock sedge, cattails, jewelweed, sphagnum, and various native true grasses are found in the bog turtle's habitat, as well as some shrubs and trees such as willows, red maples, and alders.
It is important for their habitat to have an open canopy, because bog turtles spend a considerable amount of time basking in the sunlight.
An open canopy allows sufficient sunlight to reach the ground so that the bog turtles can manage their metabolic processes through thermoregulation.
The late J. Alan Holman, a paleontologist and herpetologist, first identified bog turtle plastral remains in Cumberland Cave, Maryland (near Corriganville), which are of Irvingtonian age (from 1.8 million to 300,000 years ago).
The second discovery was of Rancholabrean (between 300,000 and 11,000 years ago) shell pieces in the Giant Cement Quarry in South Carolina (near Harleyville), by Bentely and Knight in 1998.
[23] The third discovery was found in Livingston County, NY, at the Cole Gravel Pit archaeological site (around 3900 years ago).
[8] Studies of variations in mitochondrial DNA indicate low levels of genetic divergence among bog turtle colonies.
Data indicate that the bog turtle suffered dramatic reductions in numbers – a population bottleneck – as colonies were forced south in the face of glaciation.
Receding glaciers led to the relatively recent post-Pleistocene expansion, as the bog turtles moved back into their former northern range.
[39] The northern and southern populations are at present genetically isolated, likely as a consequence of farming and habitat destruction in Virginia's Shenandoah Valley during the American Civil War.
[36] Occasionally, during times of extreme heat, the turtle will either estivate,[41] or become subterranean, sometimes occupying networks of tunnels filled with water.
[35] Bog turtles try to find an area of dense soil, such as a strong root system, for protection during the dormant period.
[40] Bog turtles are omnivorous and eat aquatic plants (such as duckweed), seeds, berries, earthworms, snails, slugs, insects, other invertebrates, frogs, and other small vertebrates.
[43] In captivity, a bog turtle can be fed a variety of fruits and vegetables, as well as meat such as liver, chicken hearts, and tinned dog food.
[17][43] In addition, leeches (Placobdella multilineata and P. parasitica) and parasitic flies (Cistudinomyia cistudinis) plague some individuals, causing blood loss and weakness.
The distance and frequency of movements on land help herpetologists understand the behavior, ecology, gene flow, and the level of success of different bog turtle colonies.
If this movement were to be prevented, or limited in any significant way, the species would have a higher likelihood of becoming extinct because genetic diversity would fall.
[30] 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.
[12] The female digs a cavity in a dry, sunny area of a bog,[17] and lays her eggs in a grass tussock or on sphagnum moss.
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.
[25] Protected under the United States Federal Endangered Species Act,[21] the bog turtle is considered threatened in Connecticut, Delaware, Maryland, Massachusetts, New Jersey, New York and Pennsylvania as of November 4, 1997.
[62] In addition to surveying land visually, remote sensing has been used to biologically classify a wetland as either suitable or unsuitable for a bog turtle colony.
[63] To help the existing colonies rebound, several private projects have been initiated in an attempt to limit the encroachment of overshadowing trees and bushes, the construction of new highways and neighborhoods, and other natural and man-made threats.