Hackles are the erectile plumage or hair in the neck area of some birds and mammals.
In birds, the hackle is the group of feathers found along the back and side of the neck.
[1] The hackles of some types of chicken, particularly roosters, are long, fine, and often brightly coloured.
[2] In mammals, the hackles are the hairs of the neck and back which become erect when the animal is fearful, as part of the fight-or-flight response,[3] or to show dominance over subordinate animals.
[5] Raised hackles are used by grey wolves as a dominance behavior,[6] by moose preparing to attack,[7] and by cats and striped hyena which are fearful or threatened.