Sea turtles are basically air-breathing reptiles native to the tropical and subtropical waters of the planet. They are found in every ocean of the world, except for the Arctic Ocean. There are different species of sea turtles, ranging from Olive Ridley sea turtles, weighing around 100 lb, to Leatherback sea turtles, weighing anywhere between 650 to 1300 lb. Sea turtles come in various shapes and sizes, each species differing from other in terms of their shell color. Found in abundance at one point of time, today these species are battling for their basic survival. Sea Turtle Species and Their Habitat Owing to the diversity in sea turtles species, their habitat extends over thousands of nautical miles in the various oceans of the world. These turtles most often inhabit the warm and temperate water in the tropics and subtropics. Other than deep oceans, their habitat spans protected bays, estuaries, and near-shore waters. Some species nest and feed in the same area, while others migrate thousands of miles for foraging. Loggerhead sea turtles, for instance, nest off the Japanese coast and migrate to the waters off the Mexican coast in search of food. Leatherback sea turtles have the ability to withstand cold temperatures and hence, they can easily survive the cold waters in south (off the coast of Chile) and north (off the coast of Alaska). These turtles spend most of their life in the oceans. Females appear on the land to lay eggs during the hatching season, but males are seldom seen out of the water. Leatherback turtles have the widest range, spanning the Pacific, Atlantic, and the Indian Ocean. Their range extends from coast of Alaska in the North to the southernmost tip of New Zealand in the south. In terms of distribution, Loggerhead sea turtles succeed the Leatherback species, with a large part of the population thriving off the coast of Oman. Hawksbill sea turtles mostly inhabit the tropical waters, but are also found in subtropical areas at times. Their largest concentration is observed in the Caribbean Sea and Seychelles. The second largest species, Green sea turtles are found in the subtropical as well as the tropical waters. Their largest concentration is noted off the coast of Costa Rica and Oman. Two of the smallest species, the Kemp's Ridley and Olive Ridley also have a global distribution. Among the various species, Flatback sea turtles have the smallest range, spanning the continental shelf and coastal waters of the tropical regions. Some Interesting Facts

• Fossil evidence traces the existence of sea turtles back to Triassic age, meaning these creatures existed around 200 million years ago.
• In some species, females store the sperms within them and produce eggs four years after mating.
• Some of these turtles have the capacity of living for a period of year or more without food.
• Growing to a length of about 6½ ft., the Leatherback turtle is the largest sea turtle species in the world.
• Male turtles seldom return to the land once they venture into the sea. On the other hand, female species turn up during the hatching season.
• If threatened by a predator, the Green sea turtle is known to swim at a speed of 20 mph.
• Amazingly enough, the Hawksbill sea turtle feeds on sea sponges which are very toxic in nature.
• Sadly, the survival rate in these turtles is very low, with some studies suggesting that only one out of a thousand hatchlings will survive.

Over the last century, sea turtles' population has depleted to a great extent. Conservationists believe that increasing demand for turtle meat, skin, and shells has led to excessive hunting of these species, which has brought about a drastic fall in their numbers. Furthermore, habitat destruction caused by pollution of ocean water has made several species vulnerable to extinction. If some action is not taken soon, there will come a point wherein we will only see or hear about sea turtles in pictures and museums.