As of 2015, three are over 10,000 reptile species in the world. This number is steadily increasing as scientists identify, describe and document more species. A reptile is an animal that has a backbone, breathes with lungs and is covered in scales. Most reptiles lay eggs and are cold-blooded.
Reptiles are classified into four orders: Crocodilia, Squamata, Testudines and Sphenodontia. These groups include snakes and lizards, which is the largest order of reptiles, accounting for more than a whopping 50 percent of the entire class. Sphenodontia is the smallest order of reptiles; it includes just two very rare reptile species.