In the right whale the species are Cyamus ovalis and Cyamus gracilis, in particular, and occasionaly C. ceti, C. erraticus, and C. catadontis. They may be eating old skin in a natural cleaning process, or available to clean wounds when needed. They may be taking food from the water that the whales swim through. Other whales, including humpbacks, have barnacles growing on their bodies. Breaching behavior may be a means of knocking this extra weight off their bodies.
Some aboriginal populations hunt small numbers of whales for food and cultural purposes.
It was reported that gray whales migrating northward past the Channel Islands off California last year had to run a gauntlet of orcas that were probably targeting calves that strayed too far from their mothers or weak, sick adults. All whales are mammals, and they have sensory organs like us. Humpback whales seem to be curious and will approach boats. Gray whales are quite mellow in their southern calving grounds. Researchers believe that whales have a highly evolved sense of hearing, using a range of sounds.