<P> Contraction of the muscles has a number of different purposes . Its principal function in the majority of mammals is to provide insulation : air becomes trapped between the erect hairs , helping the animal retain heat . Erection of the porcupine 's long , thick hairs causes the animal to become more intimidating , scaring predators . Pressure exerted by the muscle may cause sebum to be forced along the hair follicle towards the surface , protecting the hair . </P>
<P> Contraction of the muscles has a number of different purposes . Its principal function in the majority of mammals is to provide insulation : air becomes trapped between the erect hairs , helping the animal retain heat . Erection of the porcupine 's long , thick hairs causes the animal to become more intimidating , scaring predators . Pressure exerted by the muscle may cause sebum to be forced along the hair follicle towards the surface , protecting the hair . </P>
what is one major function of arrector pili muscle contraction
what is one major function of arrector pili muscle contraction
to provide insulation
to provide insulation