Backyard Ecology Creating Space for Pollinators and Wildlife
Creating Space for Pollinators and Wildlife

Common Box Turtles: Our Most Common Backyard Turtle Visitor

If you are in the eastern U.S. and find a turtle in your yard, there’s a good chance that it is a common box turtle (Terrapene carolina). Box turtles are also the turtle that you are most likely to stumble across out in the woods, or even on a hike through a meadow. Because common box turtles are our only species of box turtle in the eastern U.S., you often hear them referred to as just box turtles. The generic name “box turtle” is also generally applied to each of the different subspecies, especially in areas where you only find one subspecies.

Range map of each of the four subspecies of common box turtle found east of the Mississippi River. Photo credit: Alexandra Demucha

Four different subspecies of box turtle can be found east of the Mississippi River. Those four subspecies are the eastern box turtle (Terrapene carolina carolina), the three-toed box turtle (Terrapene carolina triunguis), the Gulf Coast box turtle (Terrapene carolina major), and the Florida box turtle (Terrapene carolina bauri). Tennessee and North Carolina have both designated the eastern box turtle as their state reptile. Just across the Mississippi River, the three-toed box turtle is Missouri’s state reptile.

Where to Find Box Turtles

Box turtles are our most terrestrial turtle. They can be found in a wide variety of habitats from woods to moist meadows, although they tend to be more commonly found in moist woods. Adult box turtles are more terrestrial than young turtles. East of the Mississippi River, the eastern box turtle is the subspecies with the largest range.

What Do Box Turtles Look Like?

All box turtles have a highly domed upper shell, called a carapace. The shape of the carapace combined with finding the turtle away from water is often enough to identify a turtle in the eastern U.S. as a box turtle. Depending on the subspecies, the carapace can be kind of an olive brownish color to a darker green color, and in most subspecies, is often patterned with different yellow or orange splotches or patches. The neck, head, and legs can also have yellow or orange stripes and patterns depending on the subspecies. However, the coloration can be highly variable. To keep things even more interesting, the subspecies can interbreed where their ranges meet or overlap, and the offspring can have a mixture of their parent’s physical characteristics.

Female box turtles typically have brownish eyes, while male box turtles typically have reddish eyes. Male box turtles also have a concave underpart of the shell, called a plastron. The plastron is relatively flat in females. Females also have long, straight, thin back claws and longer, thinner tails than males, which tend to have short, curved, thick back claws and short, thick tails.

Eastern box turtle. Photo credit: Jim Lynch, National Park Service, cc-by-sa 2.0

Box turtles are also our only turtle species that can completely close its shell. It can do this because its plastron is hinged. The hinged plastron allows the box turtle to pull its legs, tail, and head completely into its shell and clamp it shut. This classic “turtle defense” that is often mistakenly thought of as applying to all turtles, provides the box turtle with a very strong defense mechanism. Some other species can come close, but adult box turtles are our only turtles that can completely close or “box” itself into its shell. Even baby box turtles can’t completely close their shell – they are typically 3-5 years old before they can do it.

Basic Biology and Life History of Box Turtles

Once they reach adulthood, box turtles can live for decades. Commonly quoted average lifespans in the wild range from 25 to 50 years, with some reports of box turtles living for up to 100 years. Adult box turtles establish home ranges close to where they hatched. The home ranges overlap and aren’t defended like we think of home ranges being defended by many other animal species.

Each home range is typically about two and a half football fields in diameter. The box turtle will spend its entire life moving through its home range in search of food, water, shelter, and mates. They can travel up to approximately a half a football length in a single day if they want to. Box turtles have a very strong sense of where “home” is and if moved out of their home range may spend the rest of their lives search for home.

The mating season for box turtles is typically between April and October. Unlike many animals which use scents and pheromones to help identify and track down their mates, box turtles rely completely on sight. Male box turtles must actually see and recognize a female box turtle before mating can occur. The female box turtles can store sperm for up to four years and still be able to lay viable eggs, which could be a beneficial trait if you aren’t guaranteed to run into a mate every year.

Florida box turtle. Photo credit: Bob Peterson, cc-by 2.0

Egg laying takes place primarily in late April and May, although it sometimes occurs later. The female will find a nice, protected, sandy spot where she can dig a nest several inches deep. She’ll then lay 4 to 6 leathery eggs (sometimes more), before covering them up and leaving. There is no parental care involved.

If the temperature of the eggs as they are incubating in the soil is mostly 81°F or below, then they will most likely be male turtles. If the temperature of the eggs is mostly 82°F or above, then they will most likely be female turtles. The eggs will hatch after several months and the hatchlings will search for damp places, sometimes around water, where they can find lots of food. It will take them at least 5-10 years to mature.

Box turtles are active during the day. In warmer weather, they may seek shelter from the heat of the day by burrowing under moist leaves or finding another cool shady spot to rest. During the winter, they will burrow under leaves or partly into the dirt and enter a hibernation-like state. Within the eastern box turtle subspecies, turtles that are from more northern populations can take getting much colder than turtles from more southern populations. Of course, that makes a lot of sense given the differences in northern and southern winters.

Diet

Box turtles are omnivores. Their diet includes slugs, insects, dead critters, small fish, small amphibians, mushrooms (including many that are poisonous to us), mayapples, blackberries and raspberries, other fruits, roots, grasses, flowers, and much more. The young turtles tend to have a more carnivorous diet than older box turtles, but even adult box turtles include some animal content in their diets.

Conservation Concerns

Gulf Coast box turtle. Photo credit: Walker Wilson, CC BY-NC-ND 2.0

Box turtle numbers appear to be declining and several states protect box turtles. Two of the primary causes for those declines are habitat loss / fragmentation and collection for the pet trade.

Habitat loss and fragmentation

Because box turtles never leave their home range, new developments can easily take out large chunks of multiple turtles’ home ranges, if not entire home ranges. Roads cutting through a turtle’s range are also dangerous to the turtles because that means the turtles have to cross the roads as they travel through their home ranges. This becomes especially apparent in the spring when males are first seeking females and the females are seeking egg laying spots. That’s why we see so many turtles on the roads at that of year.

Collection for the pet trade

Even though box turtles live for a long time, it takes them at least 5 to 10 years to reach sexual maturity. Once they reach sexual maturity, they don’t breed every year and the female only lays a handful of eggs each year. At the population level, most of the eggs laid each year are eaten or don’t hatch for one reason or another. Only a very small percentage of the eggs laid each year actually hatch and survive to adulthood.

For a species such as the box turtle that takes a long time to mature and then only has a few individuals reach adulthood, removing additional individuals from the population can have devastating effects. Those effects are only compounded when the populations are already small or are greatly impacted by habitat loss and fragmentation. However, for a long time, box turtles were collected from the wild and sold as pets. Most states in the eastern U.S. have banned commercially collecting and selling box turtles because of the impacts it was having on the box turtle populations. Some states even have regulations banning the collection of wild box turtles for personal pets.

Three-toed box turtle. Photo credit: Thomas Shahan, cc-by 2.0

Ways We Can Help

  1. If you see a box turtle along the side of the road or in the road, and it is safe to do so, move it to the other side of the road. Just be sure to move it to the side of the road that it is already going.
  2. Don’t move box turtles outside of their home ranges.
  3. Don’t bring a box turtle that you find in the wild home for a pet.
  4. If you already have a box turtle as a pet, don’t release it into the wild. It could introduce diseases into the wild population. Plus, it will likely wander around aimlessly looking for “home” and never really adapt well to the wild.
  5. Provide “wilder” areas of your yard, when possible, where box turtles who find their way onto your property can find cover as well as yummy vegetation, fruits, and bugs to eat.
  6. If possible, before mowing taller grass, do a quick walk through to make sure you don’t have any box turtles hiding in the grass. If you do find a turtle, move it to a nearby safe location.

Summary

Common box turtles are fascinating animals and often welcomed visitors to our yards. They are considered our most common land turtle, but in many areas their populations are declining. The good news, is that there are concrete things we can do to help them.


Backyard Ecology: Creating Space for Pollinators and Wildlife
Nature isn’t just “out there.” It’s all around us, including right outside our doors. Hi, my name is Shannon Trimboli, and I am the host of Backyard Ecology. I live in southcentral Kentucky and am a wildlife biologist, educator, author, beekeeper, and owner of a nursery specializing in plants for pollinators and wildlife conservation. I started Backyard Ecology as a way to share my love of exploring nature and learning about different plants and animals. I invite you to join me as we ignite our curiosity and natural wonder, explore our yards and communities, and improve our local pollinator and wildlife habitat. Learn more or subscribe to my email list at www.backyardecology.net.

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