Fauna of Australia in Australia, feeding on sea grass in coastal areas. The destruction of sea grass beds is a threat to the survival of this species. Eleven species of seal—family Pinnipedia—live off the southern coast. Australia and its territories are home to around 800 species of bird; 45% of these are endemic to Australia. The fossil record of birds in Australia is patchy; however, there are records of the ancestors of contemporary species as early as the Late Oligocene. Birds with a Gondwanan history include the flightless ratites (the emu and southern cassowary), megapodes (the malleefowl and Australian brush-turkey), and a huge
Flightless bird that require a significant amount of overall metabolic energy, ratites decrease their basal metabolic rate and conserve energy. A study looking at the basal rates of birds found a significant correlation between low basal rate and pectoral muscle mass in kiwis. On the contrary, flightless penguins exude an intermediate basal rate. This is likely because penguins have well-developed pectoral muscles for hunting and diving in the water. For ground feeding birds, a cursorial lifestyle is more economical and allows for easier access to dietary requirements. Flying birds have different wing and feather structures that make flying easier, while flightless birds'