Editing Anti-predator adaptation (section)

=== Playing dead ===

{{main |apparent death}}

[[File:Heterodon platirhinos 2.jpg |thumb |left |[[Eastern hog-nosed snake]] [[Apparent death|playing dead]]]]

Another pursuit-deterrent signal is [[apparent death|thanatosis or playing dead]]. Thanatosis is a form of bluff in which an animal mimics its own dead body, [[deception in animals|feigning]] death to avoid being attacked by predators seeking live prey. Thanatosis can also be used by the predator in order to lure prey into approaching.<ref name=Pasteur>{{cite journal |last1=Pasteur |first1=Georges |date=1982 |title=A classificatory review of mimicry systems |journal=Annual Review of Ecology and Systematics |volume=13 |issue=1 |pages=169–199 |doi=10.1146/annurev.es.13.110182.001125 |jstor=2097066|bibcode=1982AnRES..13..169P }}</ref>
An example of this is seen in [[white-tailed deer]] fawns, which experience a drop in heart rate in response to approaching predators. This response, referred to as "alarm [[bradycardia]]", causes the fawn's heart rate to drop from 155 to 38 beats per minute within one beat of the heart. This drop in heart rate can last up to two minutes, causing the fawn to experience a depressed breathing rate and decrease in movement, called tonic immobility. Tonic immobility is a reflex response that causes the fawn to enter a low body position that simulates the position of a corpse. Upon discovery of the fawn, the predator loses interest in the "dead" prey. Other symptoms of alarm bradycardia, such as salivation, urination, and defecation, can also cause the predator to lose interest.<ref>{{cite journal |last1=Alboni |first1=Paolo |last2=Alboni |first2=Marco |last3=Bertorelle |first3=Giorgio |date=2008 |title=The origin of vasovagal syncope: to protect the heart or to escape predation? |journal=Clinical Autonomic Research |volume=18 |issue=4 |pages=170–8 |doi=10.1007/s10286-008-0479-7 |pmid=18592129 |s2cid=7739227 }}</ref>{{-}}