Fin whales are the among the fastest of all rorqual whales, reaching speeds of 37 kilometres per hour, and are known as the 'greyhounds of the sea'. This whale is light grey to brown-black in colour on the upper surface and white on the underside, flippers and fluke. The patterns on the jaw are asymmetrical, and the lower jaw is grey or black on the left and cream on the right, and there are between 50 and 100 grooves on the underside of the body which extend from the throat to the naval. While feeding, the bluish grey baleen plates are visible, which can be up to 76 centimetres long and 30 centimetres wide and are bluish to grey in colour with white fringes. The prominent dorsal fin can be up to 60 centimetres in length and curves strongly. The male and female tend to be very similar in their general appearance, but the female is slightly larger than the male.