Reptiles belong to the class Reptilia. They are a diverse group of cold-blooded invertebrates known for their scale-covered skin. There are four known orders of reptiles: Crocodilia, Rhynchocephalia, Squamota and Testudines. Reptiles are oviparous: they lay eggs.
Many reptiles display mating rituals. Some lizards have been known to change color to signal readiness to mate. Male turtles have been known to woo a female by bobbing his head or using his claws or forelimbs to caress her face.
Sexual Reproduction in Reptiles
For many reptiles, much of the reproductive activity occurs within the cloaca, the sexual and excretory opening. This opening is located at the base of the tail. A majority of reptiles possess copulatory organs. Male turtles and Crocodilians have penises. Snakes and lizards have a pair of structures known as a hemipenis. This pair of copulatory organs remains within the body until the reptile is ready to reproduce. The male reptiles penetrate the cloacas of the females to pass sperm to them. The sperm then fertilizes the eggs, which are covered with coatings and secretions before being laid. A majority of reptiles lay amniotic eggs that are covered with leathery or calcerous shell. There is no larval stage of development for reptiles.
Asexual Reproduction in Reptiles
Asexual reproduction has been positively identified in six different types of lizard and one type of snake. For this group, the offspring are exact clones of the parent. The organisms are neither male nor female and do not require a partner to reproduce. The genetic information is passed to the offspring by one parent, resulting in a genetically identical clone. This process is known as parthenogenesis.
Eggs and Hatching
The number of eggs yielded during reproduction varies greatly depending upon the type of reptile. Reptiles can lay as few as one egg or over 100 eggs at a time depending on the specific type of reptile. African tortoises can only lay 1 to 2 eggs at a time, while some sea turtles lay up to 150 eggs at once. Reptiles generally deposit their eggs in nests. These nests can be made from sand, leaves or soil. The reptiles then leave the eggs to hatch on their own. Exceptions to this include pythons, which coil around the eggs and crocodiles, which guard the nests.
All reptiles are fully developed upon hatching, however they are extremely vulnerable to attacks from predators. Many reptiles die within their first year of life. The survivors can go on to live very lengthily lifespans. Many types of turtles have been known to live well over 100 years.