No, he's not rude. Jackson the Mandrill has arthritic finger that causes him to salute his viewers at the zoo. Mark Rogers, who took the photo of Jackson's "we're number one salute" said:
‘I was there photographing him, and a father and sons were watching him,’ said Mark Rogers, who captured the finger in full flight. ‘Jackson’s a bit grumpy and really doesn’t like being photographed, but what he likes even less is people shouting at him.
‘The father tried to make fake ape sounds and Jackson raised his hand with the finger extended. The entire crowd watching him then laughed out loud and the father quickly stopped making the noise.’
Mr Rogers added: ‘I did find out later that the mandrill had arthritis in that finger. I can’t help but wonder if he used that to his advantage.’
More at Metro: Link (Photo: Caters)