Exoskeleton Animals: What Adaptation Advantages Do They Have?

Rajnandini Roychoudhury
Jan 24, 2024 By Rajnandini Roychoudhury
Originally Published on Oct 22, 2021
Edited by Luca Demetriou
There are many exoskeleton animals in the world
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Age: 3-18
Read time: 7.6 Min

Have you ever been to a zoo?

You must have seen various animals, huge and tall. However, there are special species of animals, that are smaller in size.

They are mostly found where the environment is harsh, however, they have adapted to it with their exterior strength. These are exoskeleton animals that have hard skeletal exterior shells that protect them against all kinds of harsh climates, predators, and any other external threat. They have found a way to live in such difficult situations, hunting for nutrition, surviving without dehydration, and making unlivable environments their home.

If you love reading this article, why not also read about animals with horns and animals with adaptations?

What are animals with exoskeletons called?

Arthropods are invertebrates that include animals such as grasshoppers, scorpions, centipedes, crustaceans like crabs, arachnids like spiders, and insects like beetles and butterflies.

Unlike a vertebrate, an invertebrate is solely dependent on its external form for protection. Their exoskeletons act as a suit of armor that protects them from any physical or chemical attacks. Their muscles attach directly to the body walls which gives them a lot of strength and provides more leverage. They are transformed through a process called molting. There are various types of exoskeleton animals.

Arthropods are divided into various forms.

Insects - They have jointed bodies, jointed legs, and external skeletons. The body of an insect is divided into three parts. First is the head which includes all the mouthparts. The second is the thorax includes sets of legs. The third is the abdomen which includes various digestive, reproductive, and excretory organs. They are easily able to protect themselves from their predators through flight. Examples include butterflies, moths, beetles, and mosquitoes.

Crustaceans - They are mostly found in aquatic regions and have two pairs of appendages. Crustaceans have an even segmented body that contains pairs of jointed legs and an open circulatory system. Examples include crabs, lobsters, shrimps, and woodlice.

Myriapods - They are mostly found in forested regions. They are found both, near land and water. Their appearance makes them look like worms however they are formed by legs and antennas. Examples include centipedes, millipedes, and Symphyla.

Locomotion in arthropods is very efficient. These creatures can walk, run, push, swim, burrow, fly, and more. Most arthropods have a common structure where they possess one compact body and many small legs. These high numbers of legs provide swift locomotion and more support to the main bodies. These legs of the arthropods can help drag or lift their entire body both horizontally and vertically. Each leg grips onto the surface with its claws or even the hairs in its legs. It's an alternating process that takes place back and forth to provide movement.

Another group of exoskeleton animals is called mollusks. The body structure of mollusks is different from the body structure of anthropods. As we already know that arthropods have a segmented body, however, mollusks have softer bodies covered in mucus. They have the protection of a huge shell, made of chitin, that acts as their exoskeleton, and protects them from the external environment and predators. Examples include snails, clams, squids, oysters, and scallops.

Desert Animals With Exoskeletons

A desert is a very difficult environment to live in. It is hard for all living things including plants, to survive here. There is very little rainfall in this region and the heat is extreme. Therefore, living beings find it hard to adapt. Surviving this harsh climate has revolutionized the animal kingdom. 

Mammals and birds migrate to cooler regions to prevent themselves from undergoing this harsh climate. However, the group of animals with exoskeletons are unable to do so, due to their smaller size. It is difficult for them to migrate in a big group and cover such a large distance. They have come up with a way of functioning in a pattern in this weather. In some desert animals exoskeleton has evolved over time.

Desert exoskeleton animals mostly rest during the day, protecting themselves from the heat and they go out hunting for food at night when the atmosphere is much cooler.

Examples include: dune cricket, moths, beetles, desert cockroach, grasshoppers, bees and wasps, ants, spiders, scorpions, tarantulas, millipede, centipede.

Animals With Both Endoskeleton And Exoskeleton

There are various animals on the earth that have both endoskeletons and exoskeletons. They are as follows.

Armadillos - As the name suggests, they have armors all around their body, protecting them from any external threat. They have protective plates attached to their backs that act as an exoskeleton. They also have an endoskeleton body made of bones and cartilages.

Turtles and Tortoises - These animals have an exterior shell that acts as their rib cage. This shell protects them from predators. It acts as an exoskeleton. They belong to the reptiles class which therefore tells us that there is an endoskeleton as well. Their body is made up of an endoskeleton of bones and cartilages. 

Pangolins - They are animals that are covered in tough, overlapping scales. These scales are made from chitin (a protein that makes the exoskeleton). These scales grow throughout life, along with the growth of the pangolin. They also have an endoskeleton.

Animals with both endoskeletons and exoskeletons are extremely interesting to watch.

The Function Of Exoskeletons In Animals

The exoskeleton in animals is a unique feature and a key factor for their survival. Through the exoskeleton, the animal species prevent themselves from dehydration.

The covering of the exoskeleton (an external skeleton, as the name, suggests itself) protects the animal's body by acting as a barrier between itself and the external environment. Not only does it protect the fragile internal muscles and tissues but it also acts as a bone and protects the animal from any external attack or unexpected climatic changes. The soft cuticles inside the animal are more prone to attack and damage by the microorganisms, however, the exoskeletons have an inbuilt defense system in which they secrete prophenoloxidase zymogen which is toxic to the microorganisms, and kills them instantly, while the phenoloxidase enzyme heals damaged cuticular surfaces.

It provides a rigid and supportive framework of nutrients such as calcium carbonate and chitin which protects the animal's body against predators. Not only does it give the animal support but due to its rigid-flexible joints (such as in lobsters), it also allows them free movement and swifter locomotion. 

How have exoskeletons helped animals survive?

Due to the unique external body, exoskeleton animals have an easy time adapting to various environments.

Whether it's rainy, hot, cold, or even dry as a desert, the exoskeleton animals know how to adapt well to new regions. However, due to their rigid shell, their body does not grow much and in many cases, their life span is reduced.

A combination of diverse populations, with various reproductive potential, and a mixed (long and short) life span, insects have formed a genetic resource to adapt to any environment and live off the nutrition around them. They have achieved many impressive evolutions. Insects were the first creatures to raid in new territories and live off the green plantations provided in those areas. They were the first creatures to protect themselves and use flight as a medium of defense against predators, using their highly agile bodies. They have also developed a complex social hierarchy where they have a cooperative division of labor among themselves. Not to forget, insects have also endured climatic changes, geographical upheavals, cosmic impacts, and the onset of ice land regions and mountain ranges.

Since the exoskeleton cannot grow, these animals have a particular way of changing their forms. The process is known as molting. During molting, their cells release an enzyme that digests the old skeleton and produces a new exoskeleton as their new body. Their new body is made of chitin and calcium after they have shed their old covering. The new exoskeleton is soft and flexible, which hardens with time after the blood starts to flow in their entire body.

The new form is water-resistant and therefore it helps those insects and creatures to survive in rainy weather. For preventing dehydrati0n, their bodies have in-built pores which help them to invade different territories. The flexible joints of lobsters, crabs, and the muscles and tissues of snails provide them freedom of movement.

What is an exoskeleton made of?

Humans are made up in such a way where our bones are protecting our internal organs, muscles, and tissues and our skin is the external covering.

However, animals with exoskeletons are unique in their own way. Their bodies are externally stronger with an outer skeleton which provides more support and damage control to their bodies against their environments.

Animals' exoskeletons are made up of proteins. The outer layer is a thin membrane known as the epicuticle and the inner layer is a thicker membrane, called the procuticle, made up of chitin-protein (a complex polysaccharide that is chemically similar to cellulose and calcium carbonate, common in rocks and eggshells).

Here at Kidadl, we have carefully created lots of interesting family-friendly facts for everyone to enjoy! If you liked our suggestions for exoskeleton animals then why not take a look at animals with opposable thumbs, or animals with shells. 

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Written by Rajnandini Roychoudhury

Bachelor of Arts specializing in English, Master of Arts specializing in English

Rajnandini Roychoudhury picture

Rajnandini RoychoudhuryBachelor of Arts specializing in English, Master of Arts specializing in English

With a Master of Arts in English, Rajnandini has pursued her passion for the arts and has become an experienced content writer. She has worked with companies such as Writer's Zone and has had her writing skills recognized by publications such as The Telegraph. Rajnandini is also trilingual and enjoys various hobbies such as music, movies, travel, philanthropy, writing her blog, and reading classic British literature. 

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