At least that's how scientists used to think. But that thinking has changed. Why? Because no one can design an intelligence test that is fair for all creatures. Two-handed chimps can learn sign language. But robins can't they only have wings. Goldfish would fail at tree- climbing but earn As in swimming. "I really don't make cross-species comparisons," says Marc Bekoff, a scientist from the University of Colorado in Boulder. Dogs do what they need to do to be dogs, and foxes do what they need to do to be foxes