Fin whales are brownish grey above and white below. The color pattern is asymmetrical: the lower jaw is white on the right side and dark on the left. Fin whales are second only to blue whales in length but are more slightly built. The dorsal fin is strongly curved and is about 60 cm high. Fin whales have an average of 85 throat grooves that extend to the navel. Each side of the upper jaw bears 350-400 baleen plates. At physical maturity, males and females average 19 and 20 meters in length, respectively. Adults have not been weighed, but calculations suggest that a 25 m animal could weigh as much as 70,000 kg.