The head of an ant: Chitin type

An exoskeleton supports and protects an animal's body from outside and not like the internal endoskeleton - of, for example human beings - from inside.

Many invertebrate animals (such as shelled mollusks) have exoskeletons in the sense of external hard parts. But if one speaks of an exoskeleton one mostly means that of arthropods (i.e. insects, spiders, myriapods and crustaceans).

Exoskeletons contain rigid and resistant components that fulfil a set of functional roles including protection, excretion, sensing, support, feeding and (for terrestrial organisms) acting as a barrier against desiccation. Exoskeletons first appeared in the fossil record about 550 million years ago, and their evolution has been seen as critical as a driving role in the Cambrian explosion of animals that took place subsequent to this time.

Other Languages
Afrikaans: Eksoskelet
български: Външен скелет
brezhoneg: Ezrelegenn
català: Exoesquelet
čeština: Vnější kostra
dansk: Exoskelet
Deutsch: Exoskelett
Ελληνικά: Εξωσκελετός
English: Exoskeleton
español: Exoesqueleto
Esperanto: Eksoskeleto
euskara: Exoeskeleto
français: Exosquelette
galego: Exoesqueleto
한국어: 외골격
hrvatski: Egzoskelet
Bahasa Indonesia: Eksoskeleton
Basa Jawa: Eksoskeleton
Kiswahili: Kiunzi nje
Kreyòl ayisyen: Egzoskèlèt
Latina: Exosceletus
lietuvių: Egzoskeletas
magyar: Külső váz
македонски: Егзоскелет
Nederlands: Exoskelet
नेपाल भाषा: एक्जोस्केलिटन
日本語: 外骨格
norsk nynorsk: Eksoskjelett
Plattdüütsch: Butenskelett
português: Exosqueleto
română: Exoschelet
Scots: Exoskelet
slovenčina: Exoskelet
slovenščina: Zunanji skelet
Türkçe: Dış iskelet
українська: Екзоскелет
中文: 外骨骼