Zalophus is a genus of three species of sea lions within the eared seal family of sixteen species:

1. California sea lion (Zalophus californianus) 
2. Japanese sea lion (Zalophus japonicus)
3. Galapagos sea lion (Zalophus wollebaeki)

Eared seals  include sea lions and fur seals. Together with the families of true seals and Walruses, Eared seals form the group of marine mammals known as pinnipeds.

Until recently, it was believed that the the  species were sub species of the Californian sea lion. However, recent studies of DNA suggest that these are three separate species.

Eared seals  differ from the true seals in having small external earflaps and hind flippers that can be turned to face forwards. Together with strong front flippers, this gives them extra mobility on land and an adult fur seal can move extremely fast across the beach if it has to. They also use their front flippers for swimming, whereas true seals use their hind flippers.

The Japanese sea lion is believed to have become extinct in the 1950s.

California sea lion are a highly social and intelligent species that is well adapted to a semi-aquatic life-style. They are widely used in educational programs in zoos and aquariums throughout the world because of their agility and trainability.

The Galapagos sea lion is found in the Galapagos Archipelago where it is one of the most conspicuous and numerous marine mammals. However, it is considered "endangered."

For details see California sea lion, Japanese sea lion, and Galapagos sea lion.

California sea lion. Source: David Corby/Wikipedia	Galápagos sea lion. Source: Kelley Kane/Wikipedia	Japanese sea lion (stuffed specimen at Tenn?ji Zoo, Osaka, Japan.) Source: Nkensei/Wikipedia based on Wolf et. al. (further reading #10)
Conservation Status	Conservation Status	Conservation Status

Further Reading 

1. Zalophus japonicus Aurioles, D. & Trillmich, F., 2008, IUCN (accessed April 8, 2009)
2. wollebaeki Sivertsen, 1953 Encyclopedia of Life (accessed April 8, 2009)
3. Zalophus californianus (Lesson, 1828) Encyclopedia of Life (accessed April 8, 2009)
4. Zalophus, Seal Conservation Society (accessed April 8, 2009)
5.  Zalophus, MarineBio.org (accessed, April 8, 2009)
6. Galápagos and Californian sea lions are separate species: Genetic analysis of the genus Zalophus and its implications for conservation management, Wolf, JB; Tautz, D; Trillmich, F, Frontiers in zoology, 2007.
7. Archaeology and holocene sand dune stratigraphy on Chatham Island, B. G. McFadgen, Journal of the Royal Society of New Zealand, 1994. 
8. The Pinnipeds: Seals, Sea Lions, and Walruses, Marianne Riedman, University of California Press, 1991 ISBN: 0520064984 
9. Encyclopedia of Marine Mammals, Bernd Wursig, Academic Press, 2002 ISBN: 0125513402
10. Marine Mammal Research: Conservation beyond Crisis, edited by John E. Reynolds III, William F. Perrin, Randall R. Reeves, Suzanne Montgomery and Timothy J. Ragen, Johns Hopkins University Press, 2005 ISBN: 0801882559
11. Walker's Mammals of the World, Ronald M. Nowak, Johns Hopkins University Press, 1999 ISBN: 0801857899