While turtles are not known for their speed, they are reputedly the most intelligent of reptiles. There are roughly 250 species of turtles alive today. These cold-blooded reptiles live in a variety of habitats, including deserts, forests, grasslands, lakes, marshes, ponds, rivers and the sea. Turtles that live solely on land are called tortoises.
Turtles vary greatly in size. The common bog turtle measures about four inches in length. However, the largest turtle species, the Atlantic leatherback (Dermochelys coriacca), may weigh more than 1,500 pounds and measures 12 feet from the tip of one flipper to the other.
Man has been a serious threat to the survival of many turtles. In fact, wildlife experts classify more than 40 species of turtles as endangered. Not only have we destroyed the turtle's natural habitats with pollution and construction, people have hunted them for centuries. Turtle meat and eggs are popular foods in many parts of the world. Tortoise shells are commonly used as ornaments.
Nesting
All female turtles, including aquatic species, lay their eggs on land.
When she's ready to lay her eggs, she digs a nest in the ground with her
back feet, lays the eggs and covers them with soil, sand or plants. She
then walks away and does not return, leaving the only the warmth of the
sun to hatch her young. Among the various species of turtles, the number
of eggs can range from one to 200.
Newly hatched turtles will dig their way out of nest, find food and protect themselves on their own. Many turtles live their entire life within a few miles or kilometers of where they hatched. But large numbers of sea turtles migrate thousands of miles or kilometers from their birthplace.
Senses
Scientists believe the turtle has a keen sense of sight, smell and touch.
It has been determined that turtles can hear low-pitched sounds about
as well as humans.
Environmental Survival
Turtles have a built-in survival mechanism which allows them to go into
a state of limited activity during extreme weather conditions. For species
living in cooler regions, this state is called brumation. During the winter
months, turtles will typically burrow into the mud of their pond or seek
or seek other shelter to brumate. Their body functions and metabolic processes
become very slow, and the need for oxygen is greatly decreased. The length
of time a turtle is able to brumate varies from species to species, but
eventually, they will need to come to the surface for air.
Turtles living in the desert or very warm climates, do not brumate. However, in order to survive intensely hot, dry periods, they enter similar a state of limited mental and physical activity which is called estivation.
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The Cretaceous Period: Age of Reptiles
