4 Common Groups of Reptiles

Reptiles have been in existence since prehistoric times. They are as a species older than mammals. There are nearly 8,000 species of reptiles and they are divided into four groups. Reptiles share common characteristics of egg laying, air breathing, being cold blooded and having scales covering their skin. Today it is common to see reptiles such as snakes, lizards and turtles as pets, and alligators are kept on farms for public display.

  1. Crocodilia

    • In the Crocodilia grouping are 23 species of reptiles divided into four primary groups. These include alligators, which are native to the U.S. and China; crocodiles, found in the U.S., tropical Africa, Asia and Australia; and their cousins the caimans and gharials, which live in South America and India respectively. These are water reptiles that can also thrive on land. This versatility makes them especially dangerous to prey both in and out of the water. Distinct to this group is a semi-sprawl walk that allows them to move quickly and gallop across land.

    Squamata

    • Known as the worm lizard group, Squamata has nearly 8,000 different species of lizards and snakes. It is the most species dense reptile group and makes up most all reptiles. This group includes iguanas, chameleons and geckos. Lizards have breakaway tails that regenerate. Snakes species include constrictors, boas, cobras and vipers. These snakes have quadrate bones in their mouth which allow them to consume prey much larger than they are.

    Testudines

    • There are 300 species of turtles and tortoises in the Testudines group. This group has some of the the oldest species of living reptiles. Turtles and tortoises are often thought to be the same but they are in fact very different. Turtles have webbed feet and live in the water while tortoises spend their lives mostly on land and can survive in dry areas. They have in common that they lay eggs, do not have teeth and most are omnivores.

    Sphendonitia

    • This is the smallest order of reptiles and contains only two rare species, the tuatora. Because of this the small group contains the only endangered species of reptile. Tuatoras look like lizards and they live only in New Zealand. The tuatara is the only reptile that resembles prehistoric lizards. Because of this it is often referred to as a "living fossil."