Fin whales are the fastest of all cetaceans, reaching speeds of 25 mph and known to completely clear the water. Quite impressive when measuring in at around 88 feet, they are considered the second biggest whale in existence in terms of length right after the blue whale. Despite their size these whales have a sleek, streamlined body with a V-shaped head, leading sailors to nickname them "the greyhounds of the sea". They also have a tall, dorsal fin, located about two-thirds of the way back on the body, that rises at a shallow angle from the animal's back. The species has a distinctive coloration pattern: the back and sides of the body are black or dark brownish-gray, and the ventral surface is white. The unique, asymmetrical head color is dark on the left side of the lower jaw, and white on the right side. Many individwhales have several light-gray, V-shaped "chevrons" behind their head, and the underside of the tail flukes is white with a gray border.