Natural History of the three toed box turtle
Terrapene
Note: this page just has general
information about the three toed box turtle.
There is much more information that I couldn’t fit in.
Descriptions
The three toed box turtle is a small turtle, usually 4-5
inches long. The carapace coloration
ranges from brown to yellowish. It range
encompasses much of the Midwest, including
Determining the gender of a box turtle
The easiest way for some one to tell whether a box turtle is a male or a female is to look for a concavity on the turtle’s plastron. Male will usually have a concave plastron while females usually have a flat plastron. You can also tell gender to some extent by looking at the facial color and toe shape, but this isn’t as accurate as looking at the plastron. Note: this method doesn’t work until the turtle is at least seven and most of the time it takes several years longer than that.
Left: female Right: male
Determining the age of a box turtle
There are several ways to tell the age of a box turtle. The easiest way is to count the number of rings on a turtle’s plastron. Each year a new layer of lamina grows on the turtle’s plastron and the result is something very much like tree rings. Until the turtle is ten years of age this will give a very accurate age. As the turtle gets older, its ring count gets less accurate, but you can still tell the general age until the turtle is in its late teens. By the time a turtle reaches its twenties, the rings have begun to wear off. Although it depends on how active the turtle is and how rough the ground is, the rings are usually worn completely off by the time the turtle is 30 or 40. After this age it is very difficult to tell even the approximate age of a box turtle. When a turtle get on in years, its carapace and plastron gets damaged from the constant abrasion of the soil and other object that it brushes against. By damaged, I mean the peripheral bones are worn away and the carapace looks very rough. However some very active turtles might get this damage before they are very old.
Above left: seven year old turtle Above right: turtle in its thirties or forties
Above left and right: a very old turtle. Note the shell abrasion.
Life History
Habitat
Three toed box turtles are an inhabitant of woodlands and meadows surrounding woodlands. They prefer moist areas and will usually retreat underground during droughts. A good habitat will have plenty of ground cover, such as pawpaw trees and poison ivy. Although a forest looks the same to a human observer, box turtles are much more specific on which parts of a forest they will inhabit. There is an area of forest that I have to walk through every time I go searching for turtles and I haven’t found a single turtle on that entire section. In another section I find turtles almost every time I visit it.
Activity patterns
Three toed box turtles are active from April to November in the northern part of their range. They come out of hibernation when the temperature reaches at least 7C (45F) for a period of several days.
Box turtles eat various foods including fruit, flowers and plants. Also, insects, worms, small mammals, fungi, ect. The flesh of some box turtle is poisonous to because they consume poisonous mushrooms. Box turtle are often found to conjugate under fruiting trees, taking advantage of the fallen fruit.
A box turtles home range usually consists of two to ten acres of forest. In this small patch of woodland the turtle can live its entire life. Some box turtles are transients. These box turtles are wanderers and don’t have a home range. It isn’t known why some box turtles are transients and others are homebodies. It also isn’t known if the transients ever settle down.
Egg laying takes place in early to mid summer. Box turtles lay from one to seven eggs. On my study are I have observed two clutches of two eggs and one clutch of six eggs. The quarter size turtle hatch in late summer to early fall. The hatchlings have yolk sacs that hold enough food for the turtle to survive several days without eating. After that it must find its own food.
Predators
Box turtles are preyed upon by a variety of birds, snakes, and mammals. The box turtles biggest predator is the raccoon. To defend against attacks from animals, box turtles have a shell that is much thicker than that of other Emydidae turtles in its family. They are also equipped with a hinge on their plastron that allows them to completely close themselves up. However, hatchling and juvenile turtles have a soft shell and the hinge doesn’t begin to function until the turtle is two years of age. This makes them much more vulnerable to predation than adults, and the chance that a hatchling box turtle will make it to adulthood are slim. However, enough adults survive from year to year to keep the population stable. Human activity is usually a much bigger threat to box turtles than predation.
This photo shows how the box turtle can close itself up using its hinge.
Threats
Box turtle populations over all of
If a box turtle is removed from its habitat or is killed by human activity all the offspring that it could have had for the next couple decades is lost. Box turtles have high juvenile mortality and low adult mortality. With species like the box turtle it is necessary for most of the adults to survive from year to year if the population is to survive. A human caused disturbance could easily upset this balance.
Probably the biggest threat to box turtles is the development of their habitat. When ever an area of woodlands is developed box turtle the population is destroyed and populations adjacent to the development decline. Another major threat is road. Tens of thousands of box turtles are killed annually while attempting to cross the road. This has an adverse affect on local populations. In a study conducted by Elizabeth Schwartz to determine the effects of road mortality on turtle populations she found that only 15% of adult box turtles were female. However she only conducted during April and May and the ratio of males to females probably would have been closer to 50% male 50% female if she had conducted this research later in the summer. Railroad tracks are another threat. Turtles may climb over the top of a rail and be unable to escape. They then over heat or starve to death. Two threats to box turtles that deserve special attention are collection for the pet trade and turtle racing. Both of these are needless and could be ended much easier than road mortality.
