Some skeptics of animal intelligence believe that humans, for all their perceptivity about the emotional states of members of their own kind, cannot infer similar states of other organisms.
This is clearly absurd.
Just take a look at this gorilla I saw in the zoo the other day. That this animal has a complex emotional life is betrayed by far more than the expression on her face. The motion of her eyes, the curious tilt of her head, the careful adjustments to find a comfortable spot to recline: all are suggestive that the gorilla is experiencing an intricate inner world.
For further proof that the gorilla has complicated emotions, take a look at the humans that gathered to watch her. The looks of excitement on these humans faces come undoubtedly from the unequivocal recognition that they are observing one of their own.
Scientists like to point to several explicit behavioral features to support the idea that great apes are capable of complex thought. They highlight tool use, elaborate social structures, and highly evolved problem-solving capabilities.
But for unequivocal proof that there’s more going on for a gorilla than for a fish, one need only spend a few minutes in the Jungle section of the Bronx Zoo—observing carefully the human creatures gathered there.