Coloration

The color pattern in some dolphins results from the interaction of basic components: the cape and the dorsal overlay. In some pinnipeds, the color varies with pelage; the lanugo in the small juvenile may be white and the pelage of the adult dark. Spotted dolphins are unspotted at birth and develop spots when approaching puberty. Belugas and some humpback dolphins are gray at birth but white as adults. Some small cetaceans and pinnipeds show sexual dimorphism in coloration. Individual and geographic variation is used as markers in studies of population size and population identity. Functions associated with color patterns may include camouflage against predation for or against predation, sexual recognition, heat balance, and several others. Real and apparent changes in coloration can be ephemeral or environmentally induced, e.g., through dilation of dermal capillaries for heat balance, or darkening of the skin in strandings after death.