Eastern Box Turtles in Wissahickon Valley Park: A Unique and Threatened Animal
by Susan Haidar, Environmental Education Planner, Wissahickon Environmental Center
This year has been a great one for spotting Eastern Box Turtles (Terrapene carolina) in the Andorra Natural Area, the northern end of Wissahickon Park. We had three unique animals sighted: one juvenile and two adults! We would love to know about your observations in the Wissahickon Park or nearby areas. iNaturalist database lists eleven documented sightings of the Eastern Box Turtle in or near the Wissahickon Park, and very few for the remainder of the City. However, some sightings are probably not reported due to the sensitivity of this species.
At one time, it was not unusual to observe this turtle in our woodlands. However, the Eastern Box Turtle is a species on the decline due to the factors listed below. The International Union of Conservation Naturalists lists it as a “Vulnerable” species. The Pennsylvania Fish and Boat Commission is preparing a conservation plan for this turtle. In our park lands, the turtle faces at least five threats from humans:
1) the removal of turtles for pets and the illegal pet trade
2) road crossings leading to fatalities
3) fences that prohibit their ability to roam and find mates
4) large lawn mowers injuring or killing them
5) climate change
Illegal wildlife trade is a huge, international problem. There is a growing market in Asia for Eastern Box Turtles to be sold as pets where the unique colorings of the turtles cause them to be valued at prices ranging from hundreds to thousands of dollars. The Department of Justice recently convicted several people for turtle smuggling. A recent article from NPR News profiled 38 Eastern Box Turtles recovered before being illegally shipped to Asia. A new technique in DNA testing traced these turtles’ native home to New Jersey where they were released back into the wild. Excellent news! Previously, experts thought captive turtles were not releasable because if their native area is not known, these turtles will roam endlessly searching for their original home.
Turtles are a unique type of reptile that has proven resilient to the ravages of geological time. Turtles began their evolution about 265 million years ago, before the dinosaurs. Some early turtles lacked a shell and had teeth. From their continued existence we can deduce that nature created a very robust body plan!
The Eastern Box Turtle has a high-domed upper shell called the “carapace” and a hinged lower plate called the “plastron.” If threatened, the box turtle will quickly pull its head and legs into its shell, and the front of the plastron shuts. What a great defense mechanism! Each turtle is uniquely patterned in brown, yellow, and orange colors. The carapace is made of bone, and the spine and ribs are fused to it. Covering the carapace are thirteen “scutes,” protective plates made of keratin, the same substance as our fingernails. The Box Turtle does not have teeth, but has a sharp, slightly hooked beak. It has four clawed toes on its back feet and five on its front feet. Although the high domed shell reminds us of tortoises, they are not closely related to them.
The native range of the Box Turtle includes most of the eastern United State from northern Florida to southern Maine, then west from Illinois to Louisiana. In the MidAtlantic and Northeastern states, Eastern Box Turtles generally live in mature forests, and their nearby successional communities. However, they can also live in suburban lawns, pasture and shrubby areas, and wetland environments. The forest is essential for overwintering and the hot summers; transitional open areas near forests are crucial to their reproduction.
The Box Turtle has as long life; most individuals are thought to live between 50 and 80 years in the wild. It is suspected that they can live to 100 years! Females reach sexual maturity at approximately five to fourteen years, and males reach maturity at around seven to eight years. The long period of time to reach sexual maturity could contribute to the decline of the species, given its other human-made challenges. Males can be distinguished from females by the color of their eyes (usually red for males and brown for females) and the shape of the plastron. Males’ are concave and females’ are not. Female turtles lay between four and eight eggs. Nesting season is during May and June. However, mating can occur all summer long. Since females can store sperm for up to four years, they may not mate every year! Baby turtles hatch after two months. Sex is determined by temperature of the eggs; males develop at lower temperatures than females. Young turtles are vulnerable to predators–their shells are soft and the hinged plastron develops around the fourth year. Box Turtles’ bodies are fully grown in six to seven years.
The Box Turtle is a true omnivore. It enjoys slugs, earthworms, small amphibians, insects, eggs, fruits, plants, and mushrooms. About fifty percent of its diet is protein. Young turtles are primarily carnivorous.
A Box Turtle’s range is probably several acres in size. Females will wander farther in search of a nesting site. Turtles go into a torpid state called “brumation” during winter. They will dig down into the loose forest soil, enter a leaf pile, or go into an abandoned animal burrow to overwinter. Leaves are essential for insulation. A turtle is an ectotherm, meaning their body temperature is effected by the outside temperature. As such, they are less active during the cooler temperatures of the fall and spring.
Please email us at wec@phila.gov if you have seen a Box Turtle in the Park. Please be specific on the location within the Park. If you see an Eastern Box Turtle in the Wissahickon, you have encountered an extraordinary animal!