It is not scientific to say that they are hungry when they're hunting and they're tired when their tongues are hanging out, and then say when they're playing with their children and acting joyful and happy, we have no idea if they can possibly be experiencing anything.
即使它们捕猎是因为饿了， 它们的舌头伸出来是因为累了， 但不能就此推断出 当它们和幼崽们玩耍时 它们表现出的是高兴。 我们无法了解它们真实的感受。