Sentence:  Suppose it happened to be the case that the majority of individuals raised their <WSD>hackles</WSD> only when they were truly intending to go on for a very long time in the war of attrition. The obvious counterploy would evolve: individuals would give up immediately when an opponent raised his <WSD>hackles</WSD>. 
Meaning of the word marked with <WSD> tags:  By extension (because the hackles of a rooster are lifted when it is angry), the hair on the nape of the neck in dogs and other animals; also used figuratively for humans. (from 19th c.)