Sea lions are pinnipeds characterized by external ear flaps, long foreflippers, the ability to walk on all fours, and short, thick hair. Together with the fur seals, they comprise the family Otariidae, eared seals and there are six extant and one extinct species (the Japanese sea lion) in five genera. Their range extends from the subarctic to tropical waters of the global ocean in both the Northern and Southern Hemispheres, with the notable exception of the northern Atlantic Ocean. They have an average life span of 20–30 years. A male California sea lion weighs on an average about 300 kg (660 lb) and is about 8 ft (2.4 m) long, while the female sea lion weighs 100 kg (220 lb) and is 6 ft (1.8 m) long. The largest sea lion is the Steller's sea lion which can weigh 1,000 kg (2,200 lb) and grow to a length of 10 ft (3.0 m). Sea lions consume large quantities of food at a time and are known to eat about 5–8% of their body weight (about 15–35 lb (6.8–16 kg)) at a single feeding.