The last time Emily Bland met Rishi the orang-utan, they were both still at the crawling stage.

The AD shows an office worker munching on a chocolate bar which turns out to be the bloody severed finger of an orang-utan.

"One day we saw an adolescent orang-utan called Sif wade into deep water, hunker down and then lunge forward making simple paddling movements with her arms and legs," says Russon.