Turtles are some of the oldest of reptiles, with the earliest ones dating back to about 215 million years ago. About 300
different types of turtles or species exist, spread all over the world. Research of fossilized remains has revealed that turtles predate the snakes and lizards and are one of the oldest of reptiles. In this article, I talk about
turtle life cycle which details the generic developmental cycle of most turtle species.
About TurtlesPrior to talking about the turtle life cycle, let me share some interesting facts about turtles. Turtles are reptiles characteristic by their cartilaginous or bony shell which acts as their defense mechanism. The shell develops out of their ribs and grows out to cover their whole bodies except for the limbs and head.
Turtles are ectotherms or cold blooded creatures that control their body temperature through external sources. They can contract their neck as well as legs inside their shells are protect themselves from any kind of danger. This amazing defense mechanism might be the reason turtles have survived extinction for millions of years. One of the most interesting facts about turtles is their exceptional night vision. An abundance of retinal rod cells enables them to have colored vision and they can see at light wavelengths ranging from ultraviolet to red end of the spectrum. Turtles have a beak and their jaws are used to chew food. They have no teeth but horny ridges instead that cover their jaw.
Turtle sizes range from a few inches to more than six feet. Turtle life span can be very long and the oldest known turtles have lived more than 100 years. Research has revealed that the turtle's vital organs do not show many signs of aging even when they reach a century in their ages. That is why the turtle genome is being probed currently for clues about their longevity secrets. Let us now have a look at the turtle life cycle. Read more on:
Life Cycle of a TurtleThe life cycle of all turtles is similar although the periods they spend in every developmental stage may vary. Their life is spent on land and in water as they are adapted for both mediums. Most turtles spend a majority of their life time in water. Here is a brief outline of turtle life cycle.
Turtle Life Cycle Stage 1: EggsFemale turtles visit dry sandy beaches to lay their eggs. They dig holes in the sand and lay their eggs in there and cover them in sand. Depending on the turtle species, it may lay one to about two hundred eggs. The eggs are particularly leathery and soft. They could be oblong or spherical dependent on the species.
One interesting fact about some turtle species is that the gender of the turtle hatched from the egg can depend on the incubation temperature. This is called as environment dependent or temperature dependent sex determination. In these species, low temperature incubation environment leads to a male offspring while high temperatures increases the probability of a female being bred.
The incubation period of different turtle species ranges from two weeks to as much as two to three months. The mother does not stay to protect or incubate the eggs and they are left to themselves.
Turtle Life Cycle Stage 2: HatchlingsOnce the incubation period is over, the baby turtles or hatchlings emerge out of their egg shells by breaking it using their egg tooth (a small bump on their nose). Then they squirm their way out of the sand and start moving towards the sea as if programmed to do so! This is the most dangerous period in their lives as they are hunted by crabs and birds during their flight to the sea. The ones that survive in this initial stage live out their childhood in the sea devouring animal and plant matter in the coastal continental shelf areas. These years that they spend in foraging and maturing slowly into adults are usually known as the lost years. Read more on
Turtle Life Cycle Stage 3: Adult TurtlesDepending on the species, it might be about three to five years, after which the hatchlings reach sexual maturity and become adult males and females. Some species do not start reproducing until they are twenty years of age. The adult turtles can be herbivorous or carnivorous depending on the species. In most species, males are larger than females and may have longer heads. They approach breeding areas at sexual maturity and copulate. After breeding, males return to foraging areas while females lay eggs on beaches and history repeats itself! After laying eggs they return to foraging areas. Females reproduce periodically. Thus the circle of life for turtles continues.
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Thus the turtle life cycle is typical reptilian type and yet different in many of its aspects. Most turtle species populations are dwindling and face the danger of extinction. The primary reasons are human encroachment on nesting areas and being killed for meat and eggs. Efforts need to be taken to prevent the extinction of these amazing creatures. It can only happen when we learn to share this Earth with these creatures and stop disturbing the balance of nature!
