Humans are animals.

Of course they do.

They feel love and sadness: Koko the Gorilla mourns the loss of her kitten

They feel excitement: Military Reunions with Man's Best Friend

They feel joy: Robin Williams has a tickle fight with Koko the Gorilla

My dog has nightmares, gets excited, and whimpers when she is sad. She also wags her tail when she is happy. So i think that animals do feel emotion .

I have observed it, and http://en.wikipedia.org/wiki/Emotion_in_animals

I should think they do, otherwise whats the point in bonding between two animals. Mother tigers and bears are very protective over their cubs I'm sure you've heard stories of bear attacks but it has been known for tigers to take revenge on the death of their cubs. Animals will feel anger towards any threat.

Most species have life mates that's got to be some form of bonding love between them otherwise they may not have picked them.(i do know some species pick mates based on what they see and not love but there have got to be some species out there that feel love for each other)

Do you think crying is a sign of emotion...?

Do i THINK? Yes.

The real question is, do we know? And i do not think we can know 100 percent that a dog or cat can feel emotion when we aren't a dog or cat.

I have seen videos of dogs crying and leaping up to greet someone who was away from home for a long time.