Wood Turtle Monitoring

Long-term population monitoring of Glyptemys insculpta

Project Summary

In September 2017, theTurtleRoom began a long term effort to better understand one of Pennsylvania’s most vulnerable freshwater turtles: the North American Wood Turtle (Glyptemys insculpta).

Wood Turtles have long faced a growing number of challenges across their range. Habitat loss and fragmentation have reduced the places where they can live, while road mortality and illegal collection continue to threaten populations. Understanding how these turtles use their environments, how their populations change over time, and where they are most vulnerable is an important part of protecting them.

The Wood Turtle Monitoring project is a field-based research effort. With permits from the Pennsylvania Fish and Boat Commission, theTurtleRoom staff and volunteers – including the Philadelphia Zoo’s Herpetology Department – spend time in and along Pennsylvania’s stream corridors searching for Wood Turtles.

When a turtle is found, the work begins. Each turtle is marked with a small notch in its shell, creating a unique identification that allows researchers to recognize it when the turtle is encountered again. The turtle is weighed, measured, and photographed. We also record any distinguishing characteristics. Once the information has been collected and recorded, the turtle is returned to the exact place where it was found.

The real value of this work is over time.

When a marked turtle is found again in the following years, researchers can begin to piece together its story. Repeated encounters can reveal how quickly individuals grow, how long they survive, where they move, and how populations are structured. Over time, these observations build a picture of how Wood Turtle populations are changing and what they need to survive and thrive.

Every turtle encountered adds another piece to the picture. Together, those pieces can help researchers and conservation agencies better understand the status of Wood Turtles in Pennsylvania and make more informed decisions about how to protect them for the future.

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Natural History

The North American Wood Turtle (Glyptemys insculpta) is a semi-aquatic turtle that is found in the northeastern part of North America. The carapace of G. insculpta is semi-flattened and each scute tends to have irregular grooves and growth layers as the scutes are not shed annually. North American Wood Turtles exhibit brown carapaces, with short yellow and black lines that come from the corners of each pleural scute. Each plastral scute will exhibit an odd oblong black blotch. The head, neck, and limbs will have a majority of black, with yellow, red and orange pigment on top. Average length of G. insculpta ranges from 5.5-8 inches (16-20 cm). Glyptemys insculpta are found in most New England, Mid-Atlantic, and Great Lakes states. They can range as far west as Minnesota and as far south as Virginia. When spring arrives North American Wood Turtles tend to be found in deciduous woodland streams. Early morning and in the later afternoon tend to be foraging times for this species. They will bask and seek out the sun during late morning to midday to maintain thermoregulation. It has been noted during summer months Glyptemys insculpta spends a large amount of time on land and can be found under decomposing vegetation, small puddles, and near sandy shores.

North American Wood Turtles are omnivorous, and will consume vegetation and animals on land and in water. They have been seen consuming slugs, beetles, millipedes, earthworms and even carrion. Slugs seemed to be what they favored the most when foraging. When looking for worms to consume, they will stomp the ground to imitate the rain falling to lure worms out. Like most chelonians, Glyptemys insculpta tend to avoid predators on a daily basis and prefer to be hidden or constantly on the lookout of incoming danger. They will be out either to bask or to forage for food. Studies have also shown that North American Wood Turtles can learn and understand mazes under the same conditions rats are put in. Males and females both show aggression during breeding season. Mating can occur in water or on land. Females will nest during the months of June and July and will seek out a sandy slope or a non-vegetated area near a stream. Three to five feet above the waterline is ideal for nesting.