Reptiles (Meaning and Explanation)

We explain what reptiles are, their characteristics and the types of reptiles that exist. What is their reproduction and digestive system like?

Reptiles - Blue Snake — Reptiles have a presence that is both fascinating and frightening.

What are reptiles?

We call reptiles a group of cold-blooded, quadrupedal and vertebrate animals, whose main characteristic is having skin covered in keratin scales. They are very abundant animals, especially in warm habitats, whose name comes from their way of walking: it comes from Latin reptile“that creeps.”

The reptiles appeared on Earth 318 million years ago and they were the predominant form of life during the Mesozoic (Triassic, Jurassic, Cretaceous), in the so-called “Age of the Dinosaurs”. They are evolutionarily related to amphibians and birds; and some prehistoric reptilian species gave rise to the first mammals.

In human cultures, reptiles have a presence that is both fascinating and frightening given its dry, ancient appearance, and its ferocity in the case of large predators such as crocodiles, alligators and snakes. Many have been associated with sinister powers or demonic entities, such as the famous case of the snake in the Garden of Eden narrated in the Bible.

Reptile characteristics

Reptiles - turtles — Some reptiles have a rigid shell integrated into the skeleton.

Reptiles, broadly speaking, have adapted to terrestrial life, although many species have subsequently returned to aquatic environments to prey. This means that they have pulmonary respiration, with a double circulatory system and a series of adaptations that allow them to conserve water as much as possible. Their scaly skin is tough and rough, and allows them to warm their bodies by exposing them to the sun, as reptiles cannot regulate body temperature internally.

Types of reptiles

Reptiles - crocodile — Crocodiles are terrestrial but have aquatic eating habits.

There are four large groups of reptiles:

Turtles (testudines) Adapted to aquatic and/or terrestrial habitats, they have a rigid shell that arises from the endoskeleton itself and protects the animal’s torso. They have a horny beak in their mouth and a small tail, as well as four legs.
Scaled lizards (squamata). Like lizards and snakes, which may or may not have legs, respectively, and have long bodies covered with thick and rough scales, which provide protection and prevent desiccation of the body.
Alligators and crocodiles (crocodylia) Terrestrial but with aquatic feeding habits, they are some of the fiercest reptilian predators on the African and American continents, thanks to their enormous toothed jaws and their robust muscular bodies.
Tuatara (rhynchocephalia). A group of living fossils that today includes a single genus, Sphenodonof three species, endemic to New Zealand. These are reptiles about 70cm in length and very close evolutionarily to dinosaurs.

Reptile reproduction

Reptile reproduction is sexual That is, it involves the internal fertilization of the female by the male during copulation, as well as the exchange of gametes (sex cells). Subsequently, the female deposits eggs, generally in a nest that she guards fiercely, or buried near water (like turtles). The offspring emerge from them, identical to their parents but smaller in size, without the need for metamorphosis of any kind.

Reptile digestive system

Reptiles - Iguana — There are herbivorous reptiles that swallow stones with which to grind the devoured food.

Reptiles have a simple and short digestive system, which is adapted for the decomposition of meat, since they are mostly predators. Your digestion It is, however, much slower than in mammals partly because they are incapable of chewing their food and must swallow it in large pieces (or whole in the case of boas), so it is common to see them sleeping or resting after feeding.

Also there are herbivorous reptiles Of course, lacking the possibility of chewing, they swallow stones with which to grind the devoured food, just as birds do. In addition, these rocks serve as ballast for marine species, facilitating immersion.

The dinosaurs

Reptiles - Dinosaurs. velociraptor — The name “dinosaurs” means “terrible lizards” in Latin.

During the Mesozoic Era, about 251 million years ago, reptiles dominated the earth and were the dominant group, acquiring enormous size and diversification never seen before (or since). These large reptiles existed for almost 200 million years until they became extinct in the transition from the Cretaceous period to the Cenozoic Era, 65 million years ago, for reasons that are unknown, but whose evidence points to a global catastrophe. Only fossil records remained of these creatures, which when discovered by humanity received the name dinosaursthat is, “terrible lizards” in Latin.

Reptiles in danger of extinction

Reptiles - Dwarf chameleon — The dwarf chameleon is native to South Africa.

Numerous reptilian species are today at risk of disappearing due to the actions of humans. Among them the following stand out:

Dwarf chameleon (Bradypodiontaeniabronchum). Tiny version of the ordinary chameleons, native to South Africa.
Ricord Iguana (CycluraRicordi) Endemic to the island of Hispaniola, in the Caribbean, few populations remain southwest of the Dominican Republic.
La Palma giant lizard (Gallotiaauaritae). Endemic to the Canary Islands, it has been becoming extinct since humans colonized the island of La Palma, due to the introduction of cats, agriculture and indiscriminate hunting.
Orinoco caiman (Crocodylusintermedius) It is the largest predator in Latin America, endemic to the Orinoco River region in Venezuela. It has a maximum length of 7 meters and is in critical danger of extinction.
Hawksbill Turtle (Eretmochelysimbricata) It is a species of sea turtle with a mottled body and whose meat and shells are highly coveted, which is why they have been hunted to the point of virtual extinction.
Chinese crocodile (Alligatorsinensis) Endemic to the mouths of the Yangtze River in China, it is dark green to black in color, and lives for around 40 years.

Examples of reptiles

Lizard - reptiles — Lizards can often be seen climbing the walls of American homes.

A perfect example of reptiles are the water turtles that many of us had as pets as children (Trachemysscripta), as well as common iguanas (Iguana iguana) that in many tropical countries can be seen wandering through the countryside or even through some cities. Also the Iranian crocodiles (Crocodyluspalustris) from zoos, the green anacondas of the Amazon (Eunectesmurinus) or house lizards or geckos (Hemidactylusmabouia) that we can find climbing the walls of American homes.