Some species exhibit differences in sizes depending on the stock. In the northern hemisphere, baleen whales are usually slightly smaller than their southern hemisphere counterparts. B. Body shape. This body shape reduces drag and is energy efficient for swimming. C. Coloration 1.
Most baleen whales exhibit skin color variations of black and gray.
This coloration, typical of many marine animals, provide camouflage. The result is that predators or prey do not see a contrast between the countershaded animal and the environment. Blue whales sometimes exhibit a yellowish ventral surface, a result of diatom growth. Barnacles and whale lice give a gray whale its characteristic light gray color. Some species, such as gray whales and sei whales, have white or faintly colored markings or scars.