Woodlands, rivers, marshes, and rock outcroppings (called kopjes) sustain a wide  variety of wildlife including the elusive leopard and several species of prey animals not found on the grasslands. Trees and bushes provide shelter for primates, forage for giraffe and other browsers, and shade for elephant and buffalo. Abundant bird life adds hundreds of species to this land already alive with wildlife, like no other place on earth, it is this sheer profusion and diversity of wildlife that grant Serengeti its profound and deserved distinction.