Reptile

Reptiles are cold-blooded animals found throughout the world. Reptiles are diverse in size, shape, color, and lifestyle. Reptiles are mysterious and often misunderstood - they are feared and revered. The reptiles, or Class Reptilia, include turtles, crocodiles, tuataras, lizards and snakes. Reptiles are vertebrates, as they have an internal skeleton and, usually, a backbone. They are also amniotic tetrapods and their skin protects them from drying out and their toes have claws.

Fish have scales and lay eggs. But, unlike reptiles, all fish live in the water and breathe through gills. The scales of fish and reptiles look very different and are of different composition. Fish eggs are without a shell and are deposited in water. Fish are not reptiles.

Amphibians have four legs, and often look like reptiles. But amphibians, such as salamanders and frogs, while being similarly unclean, have moist skin that does not protect them from drying out, and toes without claws. The eggs of amphibians are gelatinous and have no shell. Amphibians usually go to water or very moist places to breed and lay their eggs. Reptiles go elsewhere. Amphibians are not reptiles.

A few mammals lay eggs and a lot of them have claws. Most mammals bear their young alive, but the egg-laying duck-billed platypus and spiny anteaters are exceptions. Mammals are different from reptiles in some obvious ways: they have hair or fur and produce milk from mammary glands to feed their young. Mammals are not reptiles.

Birds have scales, claws, and they lay eggs. Bird feathers are modified scales. Bird legs are covered with scales, and their toes have claws. Birds lay shelled eggs, and they are allegedly descendants of small, meat-eating dinosaurs. Scientists who believe in evolution and who classify animals on the basis of ancestry say that birds are reptiles.