North atlantic right whale

Like other right whales, the North Atlantic right whale, also known as the northern right whale or black right whale, is readily distinguished from other cetaceans by the absence of a dorsal fin on its broad back, short, paddle-like pectoral flippers and a long arching mouth that begins above the eye. Its coloration is dark grey to black, with some individuals occasionally having white patches on their stomachs or throats. Other unique features include a large head, which makes up a quarter of its total body length, narrow tail stock in comparison to its wide fluke and v-shaped blowhole which produces a heart shaped blow. The most distinguishing feature for right whales is their callosities, rough, white patches of keratinized skin found on their heads. The right whale's callosities provide habitat for large colonies of cyamids or whale lice, which feed on the right whale's skin as these small crustaceans cannot survive in open water. The relationship between cyamids and right whales is symbiotic in nature but is poorly understood by scientists. Callosities are not caused by the external environment and are present on fetuses before birth. However, Cyamids near the blowhole have been linked to chronic entanglement and other injuries; their presence in this area has been used as measure of individual health in visual health assessments.