Expert scientists helped the producers to film animal behaviour that is rarely seen. The team 'staked out' radiotagged timber rattlesnakes in order to witness one of them despatching its prey. However, for Attenborough's close encounter with a spitting cobra, a captive snake that was used to being handled was placed in a natural setting and the presenter wore a face visor. Other examples of 'pets' being used were for sequences depicting the lassoing tongue of a chameleon (which had to be filmed at ultra-high speed) and the digestive system of a python (which was enhanced by computer-generated imagery).