Biodiversity patterns are strongly connected to land use by herbivores and human activity. Africa occupies one-fifth of the global land surface and here live a quarter of the World's approximate 4,700 mammal species and 1,600 bird species which are endemic (existing only in this area.) A great number of these species are on the environment. In Kenya the National Parks include the World famous Masai Mara, bordering the Serengeti in Tanzania, home to a number of these endangered species. Between July and October unimaginable numbers of wilderbeest, zebra, gazelles and big cats make the journey from the Serengeti in Tanzania into the Masai Mara in Kenya, crossing the border to reach grazing sites which are lush after the rains. The proposal to build a highway through the Masai Mara/Serengeti has raised grave concerns from the International Union for Conservation of Nature and The World Heritage Centre as it would cut off these migration routes, encourage poaching and desturb the habitat for these animals.