Cats are an invasive species in Australia. Because they are not native to Australia and were only introduced by colonisers as pets in the early 1800s, native Australian animals did not co-evolve with them. As of 2016, some 3.8 million domestic cats and up to 6.3 million feral cats continue to live in Australia. Every year domestic and feral cats in Australia kill 1,067,000,000 mammals, 399,000,000 birds, 609,000,000 reptiles, and92,000,000 frogs. As one of the most ecologically damaging and the most costly invasive species in Australia, predation by both domestic and feral cats has played a role in the extinction of many of Australia's Indigenous animals. For instance, cats are found to have significantly contributed to the extinction of at least 22 endemic Australian mammals since the arr