There's been a resurgence in interest from the scientific community in dogs and their behaviour recently. Collies that can recognise 200 (Rico) or 300 (Betsey) different objects by name, dogs that can understand when their owners point at things (Time). They're starting to wonder if dogs might not be more intelligent than they previous thought (like here and here).
Sad to say I can only assume from this that the people engaged in animal behavioural research do not own any dogs or cats or horses or even stick insects. Anyone who owns ... or rather shares their life with any of the above knows they are intelligent. OK, I'm not completely sure about the stick insects - we don't own any - but the rest most definitely are.
There's a great quote from Chris Bonnington (I think) when he was talking about mountaineering -
"To those who understand no explanation is necessary, to those who don't none is possible."
I think the same holds true about animal intelligence. Those who work with animals know they are intelligent, those who don't can only see the dumb animal.
Take ours (not literally - they're ours!) Dogs have a habit of turning round several times before they lie down. A primeval checking for snakes apparently. Anyway one of ours, if sat on the sofa, won't turn round if there is anything on the arm of the sofa in case she knocks it off. Instead she stands there looking pathetic until someone moves the stuff off the arm. Then she turns around and settles down. Once that's accomplished the articles can be replaced on the arm of the sofa. No one's taught her this. She's generalised it from knocking something off the arm once in the dim and distant past to any article in that place can be knocked off now. Wow! I won't tell you how many cups of tea this has saved. And like I said no one taught her this she figured it out for herself. Makes you think, huh?