I think a better standard would be how well they demonstrate their intellect when faced with a problem on their own which is challenging and for which they have strong motivation to solve.
Even human intellect varies significantly depending on motivation. A person in a life or death scenario is significant more intelligent than the same person bored and vegging out on the couch in front of the TV.
One does what one has to do when failure means death or pain.
Philosophers talk about the "private language" problem. They say you can't have a language that only one person understands because it isn't a language. Or I think that's what they say.
Cats could always be working on their own problems and coming up with brilliant solutions but if those problems and solutions don't register with experimenters they won't be judged as smart as animals working on problems recognized by human experimenters.
A person in a life or death scenario is significant more intelligent than the same person bored and vegging out on the couch in front of the TV.
House cats usually seem to be bored and vegging out on the couch. The dog who craves human attention may be interacting more with the world, and that attentiveness could be read as intelligence, rightly or wrongly.
A person in a life or death scenario is significant more intelligent than the same person bored and vegging out on the couch in front of the TV.
A solution could be brilliant, but the animal still might end up dead.
In any case experiments like that aren't going to please the animal rights crew.