Like other right whales, the North Atlantic right
whale is readily distinguished from other whales by
the callosities on its head, a broad back without a
dorsal fin, and a long arching mouth that begins above
the eye. The body of the whale is very dark grey or black,
occasionally with some white patches on the belly.
The right whale's callosities appear white, not due to skin
pigmentation, but to large colonies of cyamids or whale lice.