Adult males measure up to 78 feet (24 m) in the northern hemisphere, and 88 feet (26.8 m) in the southern hemisphere. Females are slightly larger than males. Weight for both sexes is between 50-70 tons (45,360-63,500 kg). Fin whales feed mainly on small shrimp-like creatures called krill or euphausiids and schooling fish. The present populations are estimated to be about 40,000 in the northern hemisphere and there may  be as many as 15,000-20,000 in the southern hemisphere, a small percentage of the original population levels.  (1) Fin whales are the second largest animals on earth,  after blue whales. Fin whales are possibly the cetaceans that live the longest. They can live for up to 100 years!