Fur seals and sea lions are large, charismatic carnivores that play and engage the public with both their skill and their dog-like appearance. Fur seals and sea lions are top level predators in southern Australian marine ecosystems and were harvested to near extinction 200 years ago. Fur seals are now recovering and are a common feature of islands and near-shore waters across southern Australia, and may reach pre-harvest levels in the next few decades. Sea lions, however, are still endangered and their numbers appear not to be recovering like fur seals and have declined at some locations. All species interact with fisheries, often to the detriment of both fishery and seal. This book outlines the comparative evolutionary ecology, biology, life-history, behavior, conservation status, threats, history of human interactions and latest research on the three species of otariids that live in the waters of southern Australia: the Australian fur seal, New Zealand fur seal and Australian sea lion. It also includes brief descriptions of Antarctic and Subantarctic seals that occupy the Antarctic pack-ice and remote Australian territories of Macquarie Island and Heard Island.