Don's diary

Day 1. Eight hours bouncing about in an open truck and suddenly the silence of the desert. I am at the foot of the Brandberg: 30 kilometres wide, 2,600 metres high, a huge lump of granite in the Namibian coastal desert. I am on an expedition with Roger Butlin, also from Leeds. Our long-term aim is to study the effects of isolation on the evolution of life on this island in the desert. On this, our first trip, our objectives are to find out what lives here and see if we can live here long enough to study it. I am looking for bats, Roger for insects.

Day 8

Leaner and fitter, we have established a base on the plateau at 2,000 metres, with enough food, water and equipment for at least a week. I celebrate by changing my clothes for the first time since we arrived. A shower and another change are more than ten days away. Bats and insects have been relatively scarce, but as we go higher the desert turns to dry savannah: the Brandberg is big enough to generate its own weather. This morning we found a solitary pool of water on a vast granite slab which tips dramatically over the edge of the plateau. In what passes for the wet season here, a spectacular waterfall must flow over the slab. I hope this pool will be a crucial source of water for the bats.

Day 12

Our tiny pool has been alive with bats. They fly tight figures of eight over its surface, leaving a glistening trail of water as they stoop to drink on the wing. They detect our mist nets frustratingly easily, but enough of them are caught to keep us busy - identifying, measuring and releasing to record their sonar calls. We also take a harmless wing membrane biopsy for DNA analysis. Five families of bat are found in southern Africa, and, remarkably, we have caught species from all five. We sleep under the stars, and our afternoons are spent sheltering from the heat under granite boulders. More than 4,000 years ago hunter-gatherers sheltered under the same boulders and decorated them with gazelles, lions, giraffes and other animals. The paintings are still bright and alive.

Day 14

Today we bag the summit for fun, although Roger found several species of grasshopper on the central plateau that we had not found elsewhere. After the steep slabs below the plateau camp, the going was easy, but the views no less spectacular: desert in all directions and the fog on the Skeleton Coast visible 80 kilometres to the west.

Day 18

Back at base camp after three gruelling days carrying loads down the mountain. It is dusty, it is 37xC in the shade and the temperature will be close to freezing tonight. Tomorrow we escape to showers, cold beers and beds. But I cannot wait to return.

John Altringham

Zoologist in the school of biology, University of Leeds. The diary of his adventure can be heard on Radio 4 on December 14 at 9.02pm.