There are lots of different kinds of animal intelligence, and actually a lot of debate about what "intelligence" even means. According to The Smartest Animals on the Planet by Dr. Sally Boysen, recently revised and updated with new studies and sections, you can break down animal intelligence into a few categories: social learning, mirror self-recognition, numerical abilities, language comprehension, cooperation with others, and altruism.
Most of the animals in the book are the ones you'd expect: apes, monkeys, dolphins, and parrots. But there are a whole mess of highly intelligent animals you might not expect. What we're saying is, if you really want a smart pet, don't get a dog or cat. Get a domesticated raven.
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