What Does Reptiles Mean
We explain what reptiles are, their characteristics and the types of reptiles that exist. How is its reproduction and digestive system.
What are reptiles?
We call reptiles a group of cold-blooded quadruped and vertebrate animals , whose main characteristic is having a skin covered with keratin scales . They are very abundant animals , especially in warm habitats , whose name comes from their way of walking: it comes from the Latin reptile , "that crawls."
Reptiles appeared on Earth 318 million years ago and 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 their dry, ancient appearance, and their ferocity in the case of large predators such as crocodiles, alligators and snakes. Many have been associated with sinister powers or with demonic entities, as is the famous case of the serpent in the Garden of Eden narrated in the Bible .
See also: Oviparous animals
Characteristics of reptiles
Reptiles, broadly speaking, have adapted to terrestrial life, although many species have subsequently returned to aquatic environments to prey. This means that they have lung 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, allowing them to warm the body by exposing it to the sun, as reptiles cannot internally regulate body temperature .
Their bodies are generally quadruped, although some species have lost their legs , such as snakes, and others have a rigid shell integrated into the skeleton (such as turtles). They generally have a good sense of smell and in the case of snakes a sense of touch that allows them to perceive vibrations from the ground .
It can help you: Animal respiration
Types of reptiles
There are four large groups of reptiles:
- Turtles ( testudines ). Adapted to aquatic and / or terrestrial habitats , they have a rigid shell that is born from the endoskeleton itself and protects the animal's torso. They have a horny beak in the mouth and a small tail, as well as four legs.
- Scaled lizards ( squamata ). Like lizards and snakes, they may or may not have legs, respectively, and have long bodies covered in thick, rough scales, which provide protection and prevent desiccation of the body.
- Alligators and crocodiles ( crocodylia ). Terrestrial but with aquatic eating habits, they are some of the fiercest reptilian predators on the African and American continents, thanks to their enormous toothed jaw and robust muscular bodies.
- Tuátaras ( rhynchocephalia ). A group of living fossils that today includes a single genus, Sphenodon , of three species, endemic to New Zealand. They are reptiles of about 70cm in length and evolutionarily very close to dinosaurs.
Reproduction of reptiles
The reproduction of reptiles 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). Later, the female lays eggs, usually in a nest that she fiercely protects, or buried near water (like turtles). From them emerge the young, identical to their parents but smaller, without the need for metamorphosis of any kind.
Digestive system of reptiles
Reptiles have a simple and short digestive system , which is adapted for the decomposition of meat, since they are mostly predators. Their digestion is however much slower than in mammals , in part because they are unable to chew food and must swallow it in large pieces (or complete in the case of boas), so it is usual to see them sleep or rest. after feeding.
There are also herbivorous reptiles , of course, that in the absence of the possibility of chewing, swallow stones with which to grind devoured food , just as birds do. In addition, these rocks serve as ballast for marine species, facilitating immersion.
The dinosaurs
During the Mesozoic Era, some 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. Of these creatures, only fossil records remained, which when discovered by humanity were called dinosaurs , that is, "terrible lizards" in Latin.
Reptiles in danger of extinction
Many reptilian species are today at risk of disappearing due to human action . Among them, the following stand out:
- Dwarf chameleon ( Bradypodion taeniabronchum ). Tiny version of ordinary chameleons, native to South Africa.
- Ricord's Iguana ( Cyclura Ricordi ). Endemic to the island of Hispaniola, in the Caribbean, few populations remain southwest of the Dominican Republic.
- Giant lizard of La Palma ( Gallotia auaritae ). 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 their indiscriminate hunting.
- Orinoco caiman ( Crocodylus intermedius ). 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 ( Eretmochelys imbricata ). It is a species of marine turtle with a mottled body and whose meat and shells are highly coveted, which is why they have been hunted to practically extinction.
- Chinese crocodile ( Alligator sinensis ). Endemic to the mouths of the Yangtze River in China, it is dark green to black in color, and lives for about 40 years.
More in: Endangered species
Examples of reptiles
A perfect example of reptiles are the water turtles that many of us had as children as pets ( Trachemys scripta ), as well as the common iguanas ( Iguana iguana ) that in many tropical countries can be seen roaming the countryside or even in some cities. Also the Iranian crocodiles ( Crocodylus palustris ) from zoos, the green anacondas from the Amazon ( Eunectes murinus ) or the house lizards or geckos ( Hemidactylus mabouia ) that we can find climbing the walls of American homes.