If we understand the term "creep" as described in the Dictionary of the Royal Spanish Academy, "to crawl like some reptiles", we could also classify it as animals that they drag or crawl certain animals such as the earthworm or the snail, invertebrates that move by dragging their bodies along the surface through different mechanisms. However, this type of movement is more common in reptile species, hence its name.
In this article on our site we will learn about some examples of animals that crawl and the characteristics they share with each other.
Origin of reptiles, the main animals that crawl
To go back to the origin of the reptiles we have to allude to the origin of the amniote egg, since it arose in this group of animals offering waterproof protection to the embryo and allowing its independence from the aquatic environment.
The first amniotes appeared from the Cotylosaurs, from a group of amphibians, in the Carboniferous period. These amniotes branched into two groups based on the different characteristics of their skull: the Synapsids (from which mammals have derived) and the Sauropsids (from which the rest of the amniotes, such as reptiles, have emerged). Within this last group there was also a division: the Anapsids, which include the turtle species, and the Diapsids, such as the well-known snakes and lizards.
Characteristics of crawling animals
Although each species of reptile can use different mechanisms to move by crawling on the ground, we can enumerate a long list of characteristics that they share with each other. Among them, we find the following:
- Even members (tetrapods) and short, although in certain groups such as snakes they may be missing.
- The circulatory system and the brain are more developed than in amphibians.
- They are ectothermic animals, that is, they cannot regulate their temperature.
- They usually have a longtail.
- They have epidermal scales, which can shed or remain growing throughout their lives.
- Very strong jaws with or without teeth.
- Uric acid is the product of excretion.
- They have a three-chambered heart (except crocodiles, which have four chambers).
- They breathe through lungs although some species of snakes breathe through their skin.
- They have a bone in the middle ear.
- They have metanephric kidneys.
- As for the blood cells, they present nucleated erythrocytes.
- Separate sexes, finding males and females.
- Fertilization is internal through a copulatory organ.
If you want to know more about the characteristics of these animals you can see the articleCharacteristics of reptiles.
Examples of animals that crawl
There are numerous animals that move by crawling, such as snakes, which do not have limbs. However, there are other reptiles that, despite having limbs, can also be considered crawling since their body surface is dragged along the ground when they move. In this section we will see some curious examples of animals that crawl or drag themselves to move.
Blind Adder (Leptotyphlops melanotermus)
It is characterized by being small in size, it does not have glands that secrete poison and lives underground, normally living in the gardens of numerous homes. It lays eggs, so it is an oviparous animal. As for their food, their diet is mainly based on small invertebrates, such as some species of insects.
Striped snake (Philodryas psammophidea)
Also known as sand snake, it has a thin and elongating body and measures approximately one meter. Along the body it presents several longitudinal bands of dark coloration in the dorsal part and lighter in the ventral region. It can be found in arid areas and forests, where it feeds on other reptiles. It is oviparous and has poisonous teeth at the back of its mouth (opisthoglyph teeth).
Tropical Rattlesnake (Crotalus durissus terrificus)
The tropical rattlesnake or southern rattlesnake is characterized by reaching large sizes and yellow or ocher colors on its body. It is found in fairly dry regions such as savannahs, where it feeds mainly on small animals (some rodents, mammals, etc.). This creeping animal is viviparous and also produces poisonous substances.
Green lizard (Teius teyou)
Another example of creeping animals is the green lizard, a medium-sized animal that is very striking since it has green colors intense in its body and a very elongated tail. Although it should be noted that the male has bluish colors during the reproductive stage.
Its habitat can be varied, being found in forest and grassland regions, for example. Their diet is based on invertebrates (small insects) and, in terms of their reproduction, they are oviparous animals.
Striped Skink (Eumeces skiltonianus)
It is a small lizard with short limbs and a very thin body It has dark tones with lighter bands on the dorsal region. It can be found in vegetation, rocky areas and forests, where it feeds on invertebrates such as some spiders and insects. As for their reproduction, spring and summer are the seasons chosen for mating.
Horned Lizard (Phrynosoma coronatum)
This creeping animal is normally grayish in color and is characterized by having a cephalic region with a kind of horns and a body covered with numerous spinesThe body is wide but flattened and has very short limbs to move. It lives in dry and open areas, where it feeds on insects such as ants. The months of March and May are chosen to carry out the reproduction.
Coral (Micrurus pyrrhocryptus)
This example is a long, slender reptile, which does not have a head region that is different from the rest of the body. It has a peculiar coloration, since it shows black rings along its body that are interspersed by a pair of white bands. It predominates in jungles or forests, where it feeds on other reptiles such as some smaller lizards. It is oviparous and very poisonous.
If you want to know the most poisonous animals in the world, don't miss this other article.
Common Turtle (Chelonoidis chilensis)
This land turtle is characterized by having a large, tall, dark-colored shell It lives in areas where vegetables and fruits predominate, since it is a mainly herbivorous reptile. However, sometimes it feeds on some bones and meat. It is an oviparous animal and it is common to find it as a pet in some homes.
Legless Lizard (Anniella pulchra)
Another of the more curious animals that crawl to move around is the legless lizard. It has a cephalic region indistinguishable from the rest of the body and ending in the shape of a point. It lacks limbs for movement and has very shiny scales along the body, which is characterized by grayish coloration with darker lateral bands and a yellowish belly. It is usually found in rocky areas and/or dunes where it feeds on small arthropods. The spring and summer months are the chosen ones to reproduce.
Green snake (Philodryas patagoniensis)
As its common name indicates, it generally has greenish colors but with darker tones around its scales. It is also known as the grassland snake because it predominates in open regions, such as some forests and/or grasslands, where it feeds on various animals (small mammals, birds, and lizards, among others). It lays eggs and, like other snake species, has poisonous teeth at the back of its mouth.
Other animals that crawl or creep
The list of reptiles is very extensive although, as we have mentioned in previous sections, not only these animals crawl to move. This is the case of the Roman snail or the earthworm, which experience friction between their body and the surface to carry out locomotion. In this section we will list other animals that crawl to move:
- Roman snail (Helix pomatia)
- Common earthworm (Lumbricus terrestris)
- False coral (Lystrophis pulcher)
- Sleeper (Sibynomorphus turgidus)
- Glass Viper (Ophiodes intermedius)
- Red Iguana (Tupinambis rufescens)
- Blind shingles (Blanus cinereus)
- Lampalagua (Boa constrictor occidentalis)
- Rainbow Boa (Epicrates cenchria alvarezi)
- Leatherback sea turtle (Dermochelys coriacea)
