Wicked Local photo by Barry Donahue
By Rich Eldred
The Cape Codder
CAPE COD —
In mid-winter nothing brings on thoughts of summer on Cape Cod like a discussion on box turtles.
Well, perhaps a few things do, but the box turtle (Terrepene Carolina) is undeniably a creature of summer, emerging from hibernation in April or May and not returning to a spot beneath the leaf duff until October.
Michael Jones, turtle conservationist with the state Natural Heritage and Endangered Species Program, was more than happy to talk of box turtles Saturday afternoon at Harwich Community Center in a program sponsored by Harwich Conservation Trust.
“I spend a lot of time around the country looking at box turtles in the U.S. and Mexico,” he explained.
Cape Cod is home to the Eastern box turtle, which ranges as far west as Michigan and south to Florida, but there are other species scattered through Texas and the Yucatan.
“Box turtles have been around a long time. There were fully formed box turtles 20 million years ago from the upper Midwest,” Jones noted. “That’s recent in turtle history, which goes back 225 million years. In fossil records, during the ice age, there were enormous box turtles – more than 10 inches.”
Ten inches doesn’t seem all that big until you realize current box turtles measure less than 6 1/2 inches tip to tip.
Box turtles have rather high domed shells with a yellow/orange/brown mosaic of markings but what differentiates them is the hinged plastron (the bottom shell). The hinge allows the turtle to tuck in its head, tail and legs and close up tight – safe from most predators. That’s one reason they can live to more than 100 years. Automobiles and lawn mowers could shorten that, however.
Southeastern Massachusetts is a population center for box turtles. They seem to like dry piney woods. The subfamily box turtles belong to has 10 other turtles, five of which are in Massachusetts: the box, wood, spotted and Blandings turtles and small but fetching Muhlenberg’s bog turtle, which lives only in three Berkshire County fens. That indicates the state is somewhat of a hub for the group.
“They all spend a lot of time on land relative to other turtles and all 10 species are declining,” Jones noted.
Box turtles don’t begin breeding until they’re around 15 to 20 years old. The males sport a concave plastron because they climb atop the female during mating. They cease growing at age 20 but can be aged by observing how polished (smooth) the shell is. It takes about 65 years to become totally smooth.
“We really have ancients among us,” Jones noted. “They spend May and June in open fields. In central Massachusetts, power lines are hot spots.”
Bob Prescott of Mass Audubon’s Wellfleet Bay Wildlife Sanctuary has noted they nest in power lines on Cape Cod. Open sunny sandy habitats keep the eggs warm and roots away from the eggs.
Around the state they are most abundant in the Connecticut River valley, parts of Southeastern Massachusetts and on the Outer Cape
“North Eastham to Truro is one of the hottest spots in Massachusetts,” noted Prescott. “Kingston/Plymouth is another. Before the Europeans arrived no one has an idea what was here. They were almost wiped out by deforestation and agriculture, then they came back.”
Wellfleet Bay Wildlife Sanctuary is an example. The area was farmed until 1920 or so and somewhere there must have been a remnant population.
“From there the population recovered,” Prescott said.
Prescott and his minions have since marked 300 different box turtles at the sanctuary.
“The rest of the Cape is so busy, carved up with roads, there’s very little chance on box turtles doing well,” Prescott opined.
While conventional wisdom had it that the turtles spent most of their lives in an area the size of a football field, long-term radio tracking shows periodically they wander farther and over time drift as the habitat changes. In the western part of the state, gravel pits and fields are favored locales.
“They seem to have an annual migration to a prime feeding area and back to the hibernacula,” Prescott said. “They’re most active in May and June. Then they sleep part of the summer when it’s so hot. They tend to go down into the soil.”
On Cape Cod, they can stay active until mid-October. Box turtles tend to avoid the heat of the mid-summer day, being most active early in the morning or at dusk, except on rainy or cloudy days.
Box turtles eat small bugs, slugs and worms as well as a vegetarian diet of berries, mushrooms, seeds, roots and leaves.
While turtles are killed crossing roads, Jones said mowing in fields is a worse problem.
Box turtles are a species of special concern in Massachusetts and the Natural Heritage program is compiling list of turtle hot spots. They are interested in any sightings of turtles alive or crushed on the road.