I said a rat and an eagle. Not pets. Under what circumstances would a wild rat feel joy? I bet even giving birth would not produce this emotion.
They sure do, at least what seems like joy. Most of the animals I have had the pleasure of working with rats, sharks, rabbits. They get so excited when they see someone they care about like when perhaps the caretaker or family members of theirs. Humans are different, but I don't think we're special. I think its sort of conceited to think that we are the only ones who feel love, happiness, pain, and grief.