 In the case of snakes, the complete outer layer of skin is shed in one layer.Snake scales are not discrete but extensions of the epidermis hence they are not shed separately, but are ejected as a complete contiguous outer layer of skin during each moult, akin to a sock being turned inside out.Moulting serves a number of functions – firstly, the old and worn skin is replaced, secondly, it helps get rid of parasites such as mites and ticks.