Walvis Bay

As one would expect, the desert and the dunes around Swakopmund don't support much animal life. All the more amazing, then, that just down the road Walvis Bay (the only natural harbour on the entire Namibian coast) is teeming with life - seals, dolphins, pelicans, seagulls, cormorants and other bird species I didn't recognise; there are also whales in the right season. These animals live on an abundant diet of fish - and so do the human inhabitants - nearly everyone there (60,000 people) lives off the fishing industry. The fish, in turn, live on an unusually high density of plankton - the water is opaque because of this, a dense shiny grey like mercury.

Tourists can take boat trips around the bay - the friendlier seals are encouraged to come on board the boats, rewarded with fish - at your own risk you're allowed to touch them; this is certainly the closest I've ever been to a seal - the hard outer fur is cold and wet but if you stroke against the grain there's a layer of softer fur underneath which is dry. One seal - Sally the Surfer - has learned to swim up to twin outboards when they're running at full throttle and sit on the cushion of water between them, begging for food.

Pelicans and seagulls fly after the boat, waiting for the occasional fish tossed up in the air; dolphins swim around and underneath, but they're impossible to photograph, I discovered, because they're very fast and they appear above the water for a split second - in groups of three or four - before they dive again, often going under the boat to appear on the other side. Overall, the contrast with the dunes just the other side of Walvis Bay town is absolute - arid lifeless sand on the shore, with not even a blade of grass or an insect to be seen; intense organic activity in and around the water; geobiology illustrated in its extremes.