The Skin And Hair Of The Southern Elephant Seal, Mirounga Leonina: Pre-Natal And Early Post-Natal Development And Moulting

The study detailed the embryological development of hair follicles and foetal pelage in the southern elephant seal, Mirounga leonina, identifying 10 stages of development. Follicle primordia appeared at about 8 weeks post-implantation, with definitive hair growth taking 14 weeks. Sebaceous glands developed rapidly after sweat glands, contributing to hair canal formation. The study also described the development of epidermal layers, noting the absence of a stratum granulosum and stratum lucidum, and observed the formation of muscle, collagen, elastic fibers, and blood vessels in the dermis. The first adult-type hair generation was tracked in near-term foetuses and young pups, with post-natal moulting beginning about 1 week after birth and completing in 3 weeks. The study found that foetal hairs were shed individually, while subsequent hair generations were united with the epidermis after the post-natal moult.