There’s a good reason for the box turtle’s name. A hinge on the bottom of its shell lets the land-dwelling turtle pull its legs, head, and tail inside and close it up tight — like a box.
When I was a boy living on Marine Corps Base Quantico in northern Virginia during the 1960s, box turtles were quite common. My friends and I often found the colorful turtles — with yellow, red, or orange markings on their shells and skin — plodding along through forests and fields. We often kept them as pets (which is now illegal in Virginia and Massachusetts).
But first we had to determine if they were innies or outies. Innies closed their shells tight and wouldn’t come out for long periods of time, so they didn’t make good pets, and we left them in the woods. After all, who wants a pet turtle that stays closed up in its shell for hours? Outies, on the other hand, only shut their shells for a few minutes, if at all, so they made much better pets because they were very active. We typically kept our pet box turtles for a few weeks before turning them loose.
I still find box turtles fairly frequently when I visit Quantico. But aside from a couple with radio tracking devices on them that were being followed by a biologist, I’ve never seen a wild box turtle in Massachusetts.
“The number of box turtles in Massachusetts is declining,” said Bryan Windmiller, director of field conservation for Zoo New England. “They are at best uncommon, even in parts of the state that are strongholds for box turtle populations, like southeastern Massachusetts, the Cape, and the lower Connecticut River Valley.”
Eastern box turtles are found from southeastern Maine to northern Florida, and west to Michigan and Illinois. Mike Jones, state herpetologist at MassWildlife, said box turtles are protected by law in Massachusetts and listed as a “Species of Special Concern” under the Massachusetts Endangered Species Act.
Windmiller said there are several reasons populations in Massachusetts are declining, including being struck and killed by vehicles, habitat loss, and an increase in predators such as skunks, raccoons, and foxes, which eat turtle eggs and hatchlings.
The loss of good habitat is partly from development, but also from the expansion of mature growth forests and the resulting decline in meadows, scrub, and thinly forested areas, Windmiller explained.
“Box turtles are dependent on open, sunny areas to nest, to warm themselves, and to forage for food,” said Windmiller. “That kind of habitat has gotten rare in Massachusetts. There are very few clearings — not much in the way of pastureland, abandoned agricultural land, young forest, etc. — which is a problem for box turtles.”
Poaching is also a problem. “People like to take box turtles as pets,” said Windmiller. “And there’s an international market for box turtles.”
But Windmiller and some of his colleagues from Zoo New England are working on a conservation project to assess and hopefully increase the number of box turtles in northern Middlesex County. Windmiller and his fellow biologists are also helping New Hampshire Fish and Game, which is investigating reports of box turtles in southern New Hampshire.
In addition to looking at the basic ecology and population dynamics of eastern box turtles, Windmiller said the project is trying to increase the turtles’ odds of surviving.
“We began work at the site focused on helping to increase the local box turtle population through nest protection and head-starting,” said Windmiller. The hatchling box turtles are raised in captivity for the first year, allowing them to grow to a size where they’ll be less vulnerable to predators when they’re released the following year.
“Later on, through habitat restoration and enhancement projects, supported in part by the Wharton Trust and MassWildlife, we have been able to expand our focus to also manage habitat for the benefit of rare and uncommon birds, plants, and insects.”
Julie Lisk, senior field biologist with the conservation department at Zoo New England, said the box turtle project started about six years ago. Lisk said she does most of the fieldwork, which includes radio tracking box turtles, collecting data, report writing, and follow-up on new turtle sightings.
Lisk added that the project recently enlisted the help of Koda, a dog that has been trained by Chris Bartos, assistant curator for Zoo New England, to find box turtles.
Box turtles have a high domed carapace ― the top part of the turtle’s shell – and are about 4.5 to 6.5 inches long, according to MassWildlife.
Female box turtles become sexually mature at around 13 years of age, said Windmiller. The females dig nest holes in soft, sandy soil, usually in May or June, where they lay an average of about five eggs, Windmiller explained. The baby turtles hatch from mid-August to early September.
Box turtles have a varied diet and feed on mushrooms, berries, and invertebrates such as insects and worms, said Windmiller. They’re particularly fond of slugs, and often have gooey slug slime all over their faces, which the researchers refer to as “slug mouth.”
Box turtles dig shallow holes in which to hibernate during the winter, or they may go partway into burrows dug by mammals such as woodchucks, said Windmiller.
Jones said it’s likely box turtles in Massachusetts regularly live to be 50 years old, and there is reasonable anecdotal evidence of a few box turtles reaching 100 years or more.
Lisk said box turtles are her favorite species of turtle, in part because they’re mostly terrestrial (land dwelling), which makes it easier for her to follow them.
“In general, I can see exactly where they are, which gives me a closer look into their world,” said Lisk. “This is also the longest-running turtle project I’ve been involved in, and each individual is a ‘friend’ of sorts. I get to learn about the unique personalities of each turtle.”
Don Lyman is a biologist, freelance science journalist, and hospital pharmacist who lives north of Boston. Send your questions about nature and wildlife in the suburbs to firstname.lastname@example.org.