Editing Anti-predator adaptation (section)

===Defensive structures===

Many animals are protected against predators with armour in the form of hard shells (such as most [[mollusc]]s and [[Testudinata|turtles]]), leathery or scaly skin (as in [[reptile]]s), or tough chitinous exoskeletons (as in [[arthropod]]s).{{sfn |Ruxton |Sherratt |Speed |2004 |page=198}}

A [[spine (zoology)|spine]] is a sharp, needle-like structure used to inflict pain on predators. An example of this seen in nature is in the [[sohal surgeonfish]]. These fish have a sharp scalpel-like spine on the front of each of their tail fins, able to inflict deep wounds. The area around the spines is often brightly colored to advertise the defensive capability;<ref>Thomas, Craig. Scott, Susan. (1997). ''All Stings Considered''. University of Hawaii Press. pp. 96–97.</ref> predators often avoid the Sohal surgeonfish.<ref name="Vincent1986">{{cite journal |last1=Vincent |first1=J. F. V. |last2=Owers |first2=P. |date=1986 |title=Mechanical design of hedgehog spines and porcupine quills |journal=Journal of Zoology |volume=210 |pages=55–75 |doi=10.1111/j.1469-7998.1986.tb03620.x }}</ref> Defensive spines may be detachable, barbed or poisonous. [[Porcupine]] spines are long, stiff, break at the tip, and in some species are barbed to stick into a would-be predator. In contrast, the [[hedgehog]]'s short spines, which are modified hairs,<ref name="Warwick2014">{{cite book |last=Warwick |first=Hugh |title=Hedgehog |url=https://books.google.com/books?id=wtmKAwAAQBAJ&pg=PT10 |date=15 June 2014 |publisher=Reaktion Books |isbn=978-1-78023-315-4 |page=10}}</ref> readily bend, and are barbed into the body, so they are not easily lost; they may be jabbed at an attacker.<ref name="Vincent1986"/>

[[File:Stinging Rose caterpillars, Megan McCarty65.jpg |thumb |upright |Stinging [[Limacodidae]] slug moth [[caterpillar]]s]]

Many species of slug caterpillar, [[Limacodidae]], have numerous protuberances and stinging spines along their dorsal surfaces. Species that possess these stinging spines suffer less predation than larvae that lack them, and a predator, the [[paper wasp]], chooses larvae without spines when given a choice.<ref>{{cite journal |last1=Murphy |first1=Shannon M. |last2=Leahy |first2=Susannah M. |last3=Williams |first3=Laila S. |last4=Lill |first4=John T. |date=2010 |title=Stinging spines protect slug caterpillars (Limacodidae) from multiple generalist predators |journal=Behavioral Ecology |volume=21 |issue=1 |pages=153–160 |doi=10.1093/beheco/arp166 |doi-access=free |hdl=10.1093/beheco/arp166 |hdl-access=free }}</ref>