While animals are generally viewed as inferior to humans, we give them less credit than they deserve in the intelligence department. Just like with humans comparing “book smarts” to “street smarts”, there are many different kinds of intelligence. We generally think of dogs as one of the smartest animals. It is because they have been bred to be able to effectively communicate with humans.
Pigs have been shown to have comparable intelligence to dogs. Despite this, we let them suffer for their meat. Animals in captivity know they are in captivity, and can get depressed. At times, large but intelligent animals like elephants and bears can snap.