The Galápagos sea lion (Zalophus wollebaeki) is a species of sea lion that exclusively breeds on the Galápagos Islands and – in smaller numbers – on Isla de la Plata (Ecuador). Being fairly social, and one of the most numerous species in the Galápagos archipelago, they are often spotted sun-bathing on sandy shores or rock groups or gliding gracefully through the surf. Their loud bark, playful nature, and graceful agility in water make them the "welcoming party" of the islands. This species was first described by E. Sivertsen in 1953. This species has been considered a subspecies of Zalophus californianus (called Z. c. wollebaeki) by many authors. But recent genetic data supports the Z. wollebaeki to be a separate species. The species belongs to the family Otariidae and genus Zalophus. Slightly smaller than their Californian relatives, Galápagos sea lions range from 150 to 250 cm (59 to 98 in) in length and weigh between 50 to 400 kg (110 to 880 lb), with the males averaging larger than females. Adult males also tend to have a thicker, more robust neck, chest, and shoulders in comparison to their slender abdomen. Females are somewhat opposite males, with a longer, more slender neck and thick torso.