Antarctica, one of the world’s eight major biogeographical realms, is made up almost entirely of one single bioregion—the ice-covered land mass, coastal tundra, and sea ice of the main continent—which is nearly twice the size of Australia. It contains two additional marine bioregions —the Antarctic Peninsula & Scotia Sea and the Subantarctic Indian Ocean Islands. Most of the Continental Antarctica is too inhospitable for many species to survive, but it does contain some coastal tundra. The Antarctic Peninsula & Scotia Sea bioregion, extending towards South America and including the Scotia Sea Islands, shelters an abundance of wildlife—an array of seals, whales, and nine species of penguin. The Subantarctic Indian Ocean Islands, located in the very south of the Indian Ocean, are critically important as resting and breeding areas for millions of seabirds and thousands of marine mammals.