Reptiles are air-breathing, cold-blooded vertebrates that have scaly bodies.
There are more than 10,700 extant species of reptiles, making reptiles one of the most diverse types of vertebrates in the world.
Reptiles can be found on every continent except Antarctica.
They live in a wide range of habitats. Many turtles live in the ocean, while others live in freshwater or on land. Lizards are all terrestrial, but their habitats may range from deserts to rainforests, and from underground burrows to the tops of trees. Most snakes are terrestrial and live in a wide range of habitats, but some snakes are aquatic. Crocodilians live in and around swamps or bodies of freshwater or salt water.
Reptiles are some of the longest-living and oldest animals in the world. Depending on the species, some reptiles can live over 50 years or even 200 years!
With an average lifespan of over 150 years, giant tortoises are the longest-living reptile species in the world. Adwaita, an Aldabra giant tortoise that died in 2006 in the Alipore Zoological Gardens of Kolkata, India, is believed to have lived to the age of 255 years.
Reptiles range in size from a tiny gecko, Sphaerodactylus ariasae, which can grow up to 17 millimeters (0.7 in) to the saltwater crocodile, Crocodylus porosus, which can reach 6 meters (19.7 feet) in length and weigh over 1,000 kg (2,200 lb).
Reptiles tend to avoid confrontation through camouflage. Two major groups of reptile predators are birds and other reptiles, both of which have well developed color vision. Thus the skins of many reptiles have cryptic coloration of plain or mottled gray, green, and brown to allow them to blend into the background of their natural environment.
Many species of reptile have color changing ability; the most well know are chameleons. They use their color changing abilities for attracting mates, as camoflague, and to help them regulate their temperature.
Reptile scales are dry and not slimy. The scales that cover their bodies are dry to the touch and quite impressive. Like human fingernails and rhinoceros horns, these scales are made of a strong protein called keratin. Contrary to popular belief, scales are not reptiles’ skin; their skin actually lies beneath this keratin layer, which serves many functions that help reptiles survive in the wild.
Reptiles are cold-blooded animals. This means that they don’t have the means to regulate their body temperature like warm blooded creatures. They raise their body temperature by lying in the sun or lower it by moving into the shade.
Although most snakes, turtles, lizards and other reptiles typically pose little threat to humans, some can be numbered among the deadliest creatures on the planet.
Most reptiles can see through ultraviolet light. Through ultraviolet vision, colors can be more intense and seen quite differently than humans. Reptiles with slit-like pupils can only see in black and white and are more active at night.
The fastest reptiles do not match up to the speeds recorded by mammals as their speeds do not generally go over 40 km/h (25 mph).
Reptiles are generally considered less intelligent than mammals and birds. Monitor lizards are typically considered to be the most intelligent reptiles. Monitors in captivity can easily learn to come when called and take other directions.
Generally, reptiles do demonstrate basic emotions. According to Dr. Sharman Hoppes, clinical assistant professor at the Texas A&M College of Veterinary Medicine & Biomedical Sciences, the main two are fear and aggression, but they may also demonstrate pleasure when stroked or when offered food.
With few exceptions, modern reptiles are carnivores feed on some form of animal life such as insects, mollusks, birds, frogs, mammals, fish, or even other reptiles. Some are vegetarians, eating leaves, grass, and even cactus in some cases.
Their reproductive methods and behaviors generally differ greatly from mammals, though there are some similarities. Among reptiles, differences in courtship rituals and reproduction can be quite different as well. Although most reptiles lay eggs, some are in fact livebearers. There are even some female reptiles that don’t require the presence of males to produce offspring.
Most reptile species do not care for their young, who are left to fend for themselves from birth.
Dinosaurs are a group of reptiles that dominated the land for over 140 million years. More than a thousand species of dinosaur known to have roamed Earth. During that time there was a great deal of volcanic activity and many earthquakes. Unfortunately, most were wiped out possibly by a meteor strike 65 million ago.
The name “reptile” comes from Latin and means “one who creeps.”
Reptiles offer economic, aesthetic, symbolic, and ecological values to humans. They are integral to food chains and in the reduction of agricultural pests, are part of the diet in some cultures, are used in producing leather goods, and are kept as pets. Some reptiles are considered aesthetically pleasing with their vivid colors. In religion, reptiles have served an important symbolic purpose, particularly noteworthy in the appearance of the serpent in Genesis.
Some reptiles are more closely related to birds than they are to other reptiles; e.g., crocodiles are more closely related to birds than they are to lizards.
The oldest reptile fossil, nicknamed `Lizzie the Lizard’, a stem-amniote or reptiliomorph, was found on a site in Scotland by palaeontologist Stan Wood in March 1988. The 20.3-cm (8-in) long reptile is estimated to be about 340 million years old, 40 million years older than previously discovered reptiles.
The study of living reptiles is called herpetology.