A Harris's antelope squirrel amongst the spines of the cholla cactus, where it painstakingly searches for cactus fruit - one of the only sources of moisture around. Whilst filming the amazing ...

Assistant producer Lance Featherstone removes the spines of the Cholla cactus from a glove, after David plunged it into the cactus to demonstrate its vicious defences. Team doctor Patrick Avery ...