TRIBUNE-REVIEW (Pittsburgh, Pennsylvania) 28 October 07 Admire turtles in the wild, and leave them there (Paul g. Wiegman)
When you hear the word "reptile," you might think first of huge dinosaurs poised to rip apart most everything in their path. Or, you might conjure an image of a snake, a big one, ready to do some sort of evil.
That's unfortunate because, although the dinosaurs were reptiles and snakes are reptiles, this group of animals has some far less sinister members.
First of all, to the herpetologist -- a person who studies reptiles and amphibians -- a reptile is a tetrapod and an amniote. A what and a what? Let me explain.
A tetrapod is an animal with four (tetra) feet (pod), legs or leg-like appendages.
An amniote is an animal whose embryos are protected by several membranes, whether in an egg or carried by the female. We humans are amniotes. Human embryos are carried by the mother for nine months in a sac filled with amniotic fluid. Chickens are amniotes. Their eggs have several membranes or sacs around the white and the yoke. These sacs become the filmy layer you peel off of a hardboiled egg.
Reptiles are divided into four taxonomic orders. They are the crocodiles and alligators, lizards and snakes, turtles and tortoises, and a lizard-like animal called a tuatara. Tuataras are found only in New Zealand, and there are only two species.
But wait.
Alligators have four legs. Lizards and tuataras have four legs, turtles have four legs, but snakes don't have any legs. So why are they in the reptile group, which is specifically defined as tetrapods?
For the answer, we need to look back 115 million years to when snakes evolved from four-legged lizards. This took place in the early Cretaceous Period, when dinosaurs flourished.
Over the years, snakes discovered a new means of locomotion other than walking. It might have been a result of where their prey was located or the substrate on which they hunted, such as mud or loose sand. From walking, which is difficult in mud and sand, snakes began to use their whole body to slither. The more they crawled, the more their legs degenerated, until now they have nearly disappeared.
Primitive snakes such as pythons and boa constrictors still have small nub-like legs just beneath their skin. These are remnants of upper-leg bones, and there are small spurs that protrude out from the skin. Find a python and see for yourself.
But back to the far less minacious members of the reptile family. The best example of cute and cuddly reptiles are turtles, tortoises and terrapins.
The difference between the three is not clear-cut. All three have a body that is protected by a bony or leathery shell that is an outgrowth of their ribs. Generally, turtles are aquatic, spending some or most of their life in the water. The marine great leatherback sea turtle, which can be 6 feet or more long and weigh half a ton, is at sea all of its life except to lay eggs. Fresh-water turtles are smaller. A common example in Western Pennsylvania is the snapping turtle that lives in rivers, lakes and shallow streams.
Tortoises, on the other hand, are terrestrial animals. Giant tortoises are the species found on the Galapagos Islands of Ecuador. These slow-moving creatures grow shells more than 4 feet in length, and weigh more than 600 pounds.
Terrapins are in between and not clearly defined. Usually, they are turtles that live in brackish water, a mixture of fresh and salt water.
Actually, the use of turtle, tortoise or terrapin depends on which type of English you are speaking; British, American or Australian. The above delineations are of British derivation. We Americans call just about everything a turtle except the diamondback terrapin that lives along the East Coast in brackish water. Australians follow the British.
The obvious breakdown of the aquatic turtle and the terrestrial tortoise is the box turtle found here in Western Pennsylvania. Being a land animal, the box turtle, to the British, is really the box terrapin. But we'll stick with the American version.
There are four box turtle species in North America: the eastern, Coahuilan, spotted, and ornate or desert box turtle. The eastern box turtle is divided into six subspecies that are relegated to specific regions of the continent.
Western Pennsylvania woods are inhabited by the eastern box turtle (Terrapene carolina carolina), which was given its scientific name by botanist Carl Linnaeus in 1758. It has a distinctive domed upper shell, called the carapace, with black-and-gold markings. The lower shell, the plastron, covers the soft under parts of the animal. At the front and back, the plating is hinged so the turtle can pull in its legs, head and tail and tightly close the shell. This protects the soft parts from predators such as raccoons, skunks and coyotes.
Unfortunately, the hard shell and hinged doors aren't able to protect box turtles from its worst enemy -- habitat destruction. The conversion of land for agriculture and development has reduced box turtle populations considerably. The other big threat comes from the docile nature of the animal. It doesn't take much chasing to catch a box turtle, and they are taken from the wild for commercial trade and to become family pets.
Although the temptation to take a turtle home is great, they are easily stressed, can be easily injured by dogs and cats, and demand more care than you might think. Without adequate space and a varied diet of natural foods, their immune system weakens and they easily contract diseases and die. In short, enjoy turtles in the woods and leave them there, where they are best suited.
Box turtles are omnivores. They eat insects, snails, slugs, worms, snakes and bird eggs. The aquatic snapping turtle will take fish and even ducks -- by swimming up from below, grabbing a leg with its mouth, and dragging the waterfowl below the water.
On the vegetable menu are berries, fungi, roots and flowers of a variety of plants.
Young turtles are more carnivorous, needing protein to grow. Mature turtles are more likely to be herbivores, sticking with the fruits and flowers.
Males usually are a bit larger than females. The lower shell of the male is concave toward the back, and the claws on the hind legs are short, thick and curved. These are structural differences that allow the male to mount and hold the female during mating. Also, males have red eyes, and females, yellowish-brown.
After mating, the female lays her eggs -- May through July -- in holes dug in sand or soft soil. Three to eight eggs might be in a nest, but the usual number is four or five. The female doesn't tend the nest, and in about three months the young hatch and are on their own.
Being cold-blooded animals, box turtles go into a sort of hibernation during the winter. In October or November, they find a place where the soil is soft and begin to burrow. They can go as deep as 2 feet in forest soils, mud, stream banks, old stumps or the already-dug tunnels of chipmunks or groundhogs. They will emerge in April.
One last note: Box turtles are dangerous to eat. Fungus is one of the items on their dinner menu, and they are able to eat, without a problem, mushrooms that are poisonous to humans.
So the next time you find a box turtle, don't have it for lunch.
Admire turtles in the wild, and leave them there