Development of the adult pelage in normal and hormone-injected spiny mice (Acomys cahirinus)

The dorsal pelage of the adult Egyptian spiny mouse (Acomys cahirinus) consists primarily of coarse brittle spines which differ from those of the juvenile pelage. The development of the adult pelage in juvenile spiny mice was examined in normal and estradiol- or testosterone-injected animals. Females complete the development of their adult pelage significantly faster than males. Both estradiol and testosterone injections speed pelage development in males. Testosterone causes a significant delay in the completion of the female's pelage. Studies of replacement of adult spines show that spine replacement is mosaic and slower than in other murid rodents.