Physical Characteristics Fin whales are brownish grey above and white below.
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. Reproduction Fin whales may be monogamous, as they are often seen in pairs.