In
whales, callosities are rough, calcified skin patches found on the heads of the three species of
right whales. Callosities are a characteristic feature of the whale genus
Eubalaena. Because they are found on the head of the whale and appear white against the dark background of the whale's skin, they allow the reliable identification of individuals of the species. The callosities themselves are grey, but their white appearance is due to large colonies of
whale lice,
whale barnacles and parasitic worms which reside on them. Young whales and diseased individuals are often infested with a different species of cyamid, which gives the callosities on those whales an orange hue rather than white. Callosities arise naturally and are present even in late-term whale fetuses, although the work of lice digging into the surface of the skin may make them more jagged and hard over time. Callosities are found on the upper surface of the whale's head: above the eyes, on the jawline and chin, and surrounding the blowholes. That explanation is not entirely satisfactory, because it does not account for the appearance of callosities in females. It has also been proposed that the barnacles attached to callosities are important in helping fend off attacks by
orcas. == See also ==