Namibia is known to have the largest cheetah population in the world. The Okatumba Wildlife Research project aims to find out how many there are. [Photos: Square Dog Radio]
Cheetahs are so keen to get to the "marking" trees, where the females leave their scent, that they enter the project's cages. They are then tranquillised and given radio collars.
Dummy cheetahs are used in training. This worker is learning how to use a blowpipe to fire a tranquilliser dart.
Results so far suggest that the cheetah population is currently around 4,000 - a significant increase on the 1982 estimate of 2,500.
Volunteer teams use radio-telemetry equipment to find cheetahs that have radio collars. Visual sightings are very rare so this is the most effective way to locate them.
The team also uses the technique of counting "spoor" or paw prints. The number of spoors on a road can be directly related to the number of cheetahs in the area.
On this occasion, the tracks had been made by donkeys and dogs, which could only mean there were poachers in the area.
Another good indication of cheetah numbers is the availability of their prey, such as these kudu antelope.
Cheetahs are shy and elusive. They move around mostly at night, avoiding contact with humans.
Project scientist Harald Forster shows a volunteer how to fill the tranquiliser darts. Sun, Spoor And Spots will be broadcast on BBC Radio 4 on Monday 17 December at 2100 GMT.