Addo, which was once farmland, now encompasses five biomes and about 1800 sq km, and extends to the coastline between the mouths of the Sundays and Bushman’s rivers. The coastal section includes Alexandria Dunefield, the southern hemisphere's largest and least degraded coastal dunefield, and islands with significant breeding colonies of African penguins, Cape gannets and Cape fur seals. Also worthy of note are the female beetles that bury elephant dung underground to eat, which both fertilises the soil and encourages the growth of the bright-green spekboom plants – the leaves of which are the main source of moisture for elephants and are nicknamed ‘elephant’s food’.