Dogs are equipped with hair follicles that are attached to special muscles called the "arrector pili" which are confined to the dog's neck, back and tail. When the dog is in a normal… See more

The arrector pili muscles are innervated by the sympathetic branch of the autonomic nervous system. In our canine companions, contraction of these muscles is elicited by the releas… See more

It's not correct to make unfounded claims that dogs who raise their hackles are aggressive. First of all, it's wrong to label dogs as aggressive from the get-go, as dogs aren't … See more

The sensation of cold has been associated in several animals with the activation of the sympathetic nervous system causing the contraction of the arrector pili muscles. The piloere… See more