Studies have shown that as countries’ life expectancy increases, so does their numbers of endangered and invasive species. New Zealand, Australia, Indonesia, the Philippines and the United States had the highest percentages of birds and mammals that are endangered and invasive. These countries also rank among those with the highest life expectancy. Countries in the continent of Africa have the lowest percentage of invasive and endangered birds and mammals. This study also found that as a country’s per capita GDP increased, so did the percentage of invasive birds and mammals.