Tracks in the sand of the Namib desert. The black rhinoceros can't be far ... the 47-year-old head of the group's base in Palmwag in north-western Namibia. It is from the local lodge that tours start ...

This story appears in the June 2011 issue of National Geographic magazine. At dawn, three weeks before the winter solstice, the last tendrils of fog curled gray against the pinking sky over a sand ...