What Are Reptiles (Characteristics and Examples)

Are Vertebrate animals of prehistoric origin that have inhabited the planet for 350 million years. They live in the land surface and in some aquatic ecosystems. They are the evolutionary descendants of the dinosaurs.

Examples of reptiles are the common iguana, chameleon, alligator snapping turtle, cobra, Komodo dragon, and horned lizard.

The most common physical characteristics of reptiles are the following:

  • They have skin covered with scales.
  • They have two holes on the top of their heads, above their eyes.
  • They are tetrapods: they have four limbs, and if they don’t, they are evolutionary descendants of species that do.
  • They have a three-chambered heart and two aortic arteries.
  • They are oviparous: the embryos develop inside eggs.
  • They metabolize food slowly.
  • They can change your body temperature.

tuat-2The tuatara (Sphenodon spp), from New Zealand, has all the typical features of a reptile and is evolutionarily the most direct descendant of the dinosaurs.

reptile species

There are more than 7,500 species of reptiles registered globally, but this number can vary depending on two factors.

  • The discovery of new species.
  • The extinction of existing species.

Lizards and snakes make up 70% of known species. However, there are other recorded species.

Currently, with the development of the field of genetics, the official classification of reptiles is a matter of debate. The classification shown below is the latest official classification on which there was consensus (excluding amphibians). It was established based on the findings of Edward Tyson (1683) and John Roy (1693).

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reptile type Example Number of species
lizards green Iguana More than 4300


More than 2900


Brothers Island Tuatara






Caiman of the Orinoco


reptile size

The size of reptiles is very diverse. The Madagascar dwarf chameleon is the smallest known reptile: it measures 30 millimeters on average. The Nile crocodile can be up to six meters long and the anaconda up to nine meters long.

serp-cascabThe Rattlesnake (Crotalus atrox) can reach 2.5 meters in length.

reptile diet

Their solid diet is based on animal protein, wild fruits and vegetables, but varies depending on the species.

For example: the land turtle is a vegetarian, it eats flower petals, fresh leaves, carrots and strawberries. In contrast, the rattlesnake is carnivorous, feeding on small rodents such as wild mice or bird eggs.

The water content consumed by reptiles represents up to 2.7% of their body weight.

green Iguanagreen iguanas (Iguana-Iguana) eat melon, parsley and zucchini among others.

reptile habitat

They are distributed throughout the planet, except in Antarctica, and there is a greater abundance and variety of species in tropical and temperate zones. However, there are species, such as the dune lizard in Namibia, that have developed the ability to survive extreme climates.

99% of reptiles are adapted to terrestrial environments; however, it is normal to find them in humid habitats, in lakes and in swamps.

Only some varieties have specialized to tolerate extreme environments such as brackish waters (in river deltas) or arid areas (deserts).

giant-galThe giant Galapagos tortoise (Chelonoidis nigra) is only found on the Galapagos Islands (Ecuador).

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reproduction of reptiles

The reproduction of reptiles is sexual and the embryos grow inside eggs (oviparous).

In general, birth occurs from eggs that have been released and incubated outside the mother. There are few species of reptiles that evolved in such a way that the newborns are released from the egg while still inside the womb (ovoviviparous).

crocod-orinocThe nests of the caiman of the Orinoco (Crocodylus intermedius) are at least 30 cm deep and the male provides food while the female protects the nest.

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