The box turtle: an evolutionary success

If turtles were known only from fossil evidence, they would be considered to be zoological curiosities because no other animals with backbones have ever been so well protected. During medieval times, humans most certainly had turtles in mind when they designed armor to protect themselves in battle, and bulletproof vests and flak jackets are modern versions of the same idea. Evidence from paleontology indicates turtles evolved some 175,000,000 years ago at about the same time as the ancestors of the dinosaurs. This was the beginning of the period in the earth’s history when the land was ruled by giant reptiles. The turtles of that time went slowly and unobtrusively on their way and may have smiled a toothless smile as they watched the dominant dinosaurs eventually become extinct. Though the primitive turtles did not give rise to a plethora of separate species as some other evolving animal groups did, the group, as a whole, should be considered as an evolutionary success story. Approximately 10 species of turtles are known to inhabit this part of northern Illinois, with the box turtle being the one most commonly observed. Whereas most turtles have the protective shell covering both the upper and lower portions of their bodies and can withdraw the head and neck back into the shell when endangered, the box turtle goes one step beyond. The box turtle’s shell offers a refinement in protective anatomy. The front and rear portions of the lower shell are hinged so that they can be pulled up tightly against the upper shell. When the animal senses danger, it draws into the shell and slams shut both the front and rear doors and is quite isolated and safe from any would-be enemy. Box turtles live entirely on land and lack the webbed feet of their kin that frequent aquatic environments. The shell is colored black and yellow or orange and brown and is about five inches long and three inches wide. The eyes of the male are red, and those of the female are brown. Automobiles kill many slow, meandering box turtles on the roads of the Rock River Valley and elsewhere. Recently, I was cruising one of the numerous rural roads in our area and passed a box turtle hunkered down in the middle of the road and completely withdrawn into its shell. It was only a matter of time until some passing vehicle crushed the frightened animal beneath its wheels, so, at risk of life and limb, I made a U-turn and picked it up as I slowly drove by. This vagabond turtle was released into the wooded area behind my house in Loves Park, where I hope the natural environment will curb its lust for wandering onto streets and roads. The box turtle prefers dry woods for a home and flourishes in warm weather, seeking shelter under logs on cool nights. As winter approaches, it digs a burrow in the ground about 15 inches deep wherein it hibernates until spring. In early summer, the female deposits three to eight eggs with thin, flexible, white shells. The eggs are laid in a cavity the mother turtle scoops out in the ground. After covering the depository, her maternal obligation is finished. The eggs hatch in about three months, and the young reptiles must fend for themselves. The newly hatched youngsters are relatively defenseless until their shells harden into a protective suit of armor. This animal enjoys a relatively long life span, with several having been observed to live more than 40 years. They are beneficial because they relish slugs and insect garden pests, and their presence should be encouraged. Box turtles are harmless and it is next to impossible to induce one to nip your finger. Turtles are toothless, but their bony beaks are effective in reducing food to small bits for swallowing. Always, when a finger or some other object is brought close to the head, the animal will retreat into its shell and close the front and rear doors. The large snapping turtle, which is also common in our region, is another story. If molested, a snapper will strike at its tormentor with the speed of a rattlesnake and can inflict a serious bite. Many a young naturalist has maintained a box turtle as an interesting pet. By providing vegetation for shade, fruits and vegetables to eat, and shallow water for drinking and soaking, ideal living quarters may be established, and the turtle may be observed and studied. A question that is frequently asked is what is the difference between a turtle, a terrapin, and a tortoise? A terrapin is a turtle that is found in water and usually good to eat, a tortoise is a turtle that lives exclusively on land, and a turtle may be either one or the other. So, any creature that looks like a turtle, acts like a turtle, and has a shell like a turtle may be correctly called a turtle. Dr. Robert Hedeen is a retired professor emeritus of biological sciences in the University of Maryland system.

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