Editing Predation (section)

== Coevolution ==
{{further|Coevolution}}
[[File:Big-eared-townsend-fledermaus.jpg|thumb|left|Bats use [[Animal echolocation|echolocation]] to hunt moths at night.]]

Predators and prey are natural enemies, and many of their adaptations seem designed to counter each other. For example, bats have sophisticated [[Animal echolocation|echolocation]] systems to detect insects and other prey, and insects have developed a variety of defences including the ability to hear the echolocation calls.<ref>{{harvnb|Jacobs|Bastian|2017|page=4}}</ref><ref>{{cite book |last1=Barbosa |first1=Pedro |last2=Castellanos |first2=Ignacio |title=Ecology of predator-prey interactions |date=2005 |publisher=Oxford University Press |isbn=9780199874545|url=https://archive.org/details/ecologypredatorp00barb|url-access=limited |page=[https://archive.org/details/ecologypredatorp00barb/page/n96 78]}}</ref> Many pursuit predators that run on land, such as wolves, have evolved long limbs in response to the increased speed of their prey.<ref name=Janis>{{cite journal |last1=Janis |first1=C. M. |last2=Wilhelm |first2=P. B. |year=1993 |title=Were there mammalian pursuit predators in the Tertiary? Dances with wolf avatars |journal=Journal of Mammalian Evolution |volume=1 |issue=2|pages=103–125 |doi=10.1007/bf01041590| s2cid=22739360 }}</ref> Their adaptations have been characterized as an [[evolutionary arms race]], an example of the [[coevolution]] of two species.<ref name=DawKrebs>{{cite journal |author1=Dawkins, Richard |author1-link=Richard Dawkins |author2=Krebs, J. R. |author2-link=John Krebs, Baron Krebs |year=1979 |title=Arms races between and within species |journal=Proceedings of the Royal Society B: Biological Sciences |volume=205 |issue=1161 |pages=489–511|doi=10.1098/rspb.1979.0081 |pmid=42057 |bibcode=1979RSPSB.205..489D |s2cid=9695900 }}</ref> In a [[gene centered view of evolution]], the genes of predator and prey can be thought of as [[Competition (biology)|competing]] for the prey's body.<ref name=DawKrebs/> However, the "life-dinner" principle of Dawkins and Krebs predicts that this arms race is asymmetric: if a predator fails to catch its prey, it loses its dinner, while if it succeeds, the prey loses its life.<ref name=DawKrebs/>

[[File:Micrurus fulviusHolbrookV3P10AA.jpg|thumb|upright=0.7|[[Micrurus fulvius|Eastern coral snake]], itself a predator, is venomous enough to kill predators that attack it, so when they avoid it, this behaviour must be inherited, not learnt.]]

The metaphor of an arms race implies ever-escalating advances in attack and defence. However, these adaptations come with a cost; for instance, longer legs have an increased risk of breaking,<ref name=Abrams>{{cite journal |last1=Abrams |first1=Peter A. |title=Adaptive responses of predators to prey and prey to predators: The failure of the arms-race analogy |journal=Evolution |date=November 1986 |volume=40 |issue=6 |pages=1229–1247 |doi=10.1111/j.1558-5646.1986.tb05747.x|pmid=28563514 |s2cid=27317468 |doi-access=free }}</ref> while the specialized tongue of the chameleon, with its ability to act like a projectile, is useless for lapping water, so the chameleon must drink dew off vegetation.<ref name=Brodie>{{cite journal |last1=Brodie |first1=Edmund D. |title=Predator-Prey Arms Races |journal=BioScience |date=July 1999 |volume=49 |issue=7 |pages=557–568 |doi=10.2307/1313476|jstor=1313476 |doi-access=free }}</ref>

The "life-dinner" principle has been criticized on multiple grounds. The extent of the asymmetry in natural selection depends in part on the heritability of the adaptive traits.<ref name=Brodie/> Also, if a predator loses enough dinners, it too will lose its life.<ref name=Abrams/><ref name=Brodie/> On the other hand, the fitness cost of a given lost dinner is unpredictable, as the predator may quickly find better prey. In addition, most predators are generalists, which reduces the impact of a given prey adaption on a predator. Since specialization is caused by predator-prey coevolution, the rarity of specialists may imply that predator-prey arms races are rare.<ref name=Brodie/>

It is difficult to determine whether given adaptations are truly the result of coevolution, where a prey adaptation gives rise to a predator adaptation that is countered by further adaptation in the prey. An alternative explanation is ''escalation'', where predators are adapting to competitors, their own predators or dangerous prey.<ref>{{cite journal |last1=Vermeij |first1=G J |title=The Evolutionary Interaction Among Species: Selection, Escalation, and Coevolution |journal=Annual Review of Ecology and Systematics |date=November 1994 |volume=25 |issue=1 |pages=219–236 |doi=10.1146/annurev.es.25.110194.001251|bibcode=1994AnRES..25..219V }}</ref> Apparent adaptations to predation may also have arisen for other reasons and then been co-opted for attack or defence. In some of the insects preyed on by bats, hearing evolved before bats appeared and was used to hear signals used for territorial defence and mating.<ref>{{harvnb|Jacobs|Bastian|2017|page=8}}</ref> Their hearing evolved in response to bat predation, but the only clear example of reciprocal adaptation in bats is stealth echolocation.<ref>{{harvnb|Jacobs|Bastian|2017|page=107}}</ref>

A more symmetric arms race may occur when the prey are dangerous, having spines, quills, toxins or venom that can harm the predator. The predator can respond with avoidance, which in turn drives the evolution of mimicry. Avoidance is not necessarily an evolutionary response as it is generally learned from bad experiences with prey. However, when the prey is capable of killing the predator (as can a [[coral snake]] with its venom), there is no opportunity for learning and avoidance must be inherited. Predators can also respond to dangerous prey with counter-adaptations. In western North America, the [[common garter snake]] has developed a resistance to the toxin in the skin of the [[rough-skinned newt]].<ref name=Brodie/>