What is Defence against predators?
[[File:Jock, the Gorilla (2).jpg|thumb|250px|Strength of the arms is the [[gorilla]]'s main defence against predators.]] [[File:Epipedobates tricolor close.jpg|250px|thumb|The skin of the [[phantasmal poison frog]] contains the toxin ''epibatidine'']] For most animals, '''defence against predators''' is vital. Being eaten is not the only threat to life: [[parasite]]s and [[disease]]s may also be fatal. But many animals are [[carnivore]]s, and others, especially small animals, are often eaten. Since life is about [[reproduction]], anything that keeps a creature alive long enough for it to reproduce will be [[natural selection|selected]] for. The next [[generation]] comes from the [[Fertilisation|fertilised]] eggs of the previous generation. Not surprisingly, then, animals have developed a wide range of defences against predation.<ref name=Edmunds>Edmunds M. 1974. ''Defence in animals: a survey of anti-predator defences''. Longmans, London. {{ISBN|0-582-44132-3}}</ref><ref name=Ruxton>Ruxton G.D. Sherratt T.N. and Speed M.P. 2004. ''Avoiding attack: the evolutionary ecology of crypsis, warning signals & mimicry''. Oxford University Press. {{ISBN|0-19-852860-4}}</ref> Some of these defences apply also to [[plant]]s: [[herbivore|herbivory]] on plants can be very damaging, and reduce a plant's fertility. Many plants have some [[defence against herbivores]]. == Primary defences == Primary defences make it less likely that there will be a meeting between the [[predator]] and the [[prey]]. In many cases this means the predator has not [[wikt:notice|noticed]] or [[wikt:recognise|recognised]] the prey.<ref>Alcock, John 2009. ''Animal behavior: an evolutionary approach''. 9th ed, Sinauer: Chapter 8 Avoiding predators and finding food. {{ISBN|0-87893-505-3}}</ref> === Definitions === There are various definitions of what a primary defence is: *Robinson 1969: those defences which operate before a predator starts any prey-catching behaviour.<ref>Robinson M.H. 1969. Defences against visually hunting predators. ''Evolution