people are animals we seem to have a hard time understanding that. but as far as us compared to cats and dogs... i wouldnt say happier. but they don't have to worry about getting up early for work, buying their girlfriend a gift, or looking the best they can.
Cats and dogs live more in the moment and don't think very far ahead, which should make it much easier for them to be happy. They also don't constantly compare themselves to others and are content with the little they have.
The constant nagging of worry of future and past is what drags humans down.