Located off the southeast coast of Africa, Madagascar is the fourth largest island in the world, measuring almost 1,000 miles north to south. It is widely considered among the top ten wildlife conservation priorities in the world because of the high diversity of species that exist only on the island and the very high rates of habitat loss due to human disturbance. Scientists believe that humans arrived on Madagascar from Indonesia about 2,000 years ago, and since their arrival may have contributed to the extinction of most of Madagascar's large animals, including the elephant bird, the largest bird to ever walk on earth, a pygmy hippopotamus, and at least 14 lemur species.