Do animals experience jealousy?

From the following article:

Humans Aren’t The Only Animals To Experience Jealousy — Dogs Do, Too

It says:

Jealousy is a fairly common human emotion — and for a long time, it was presumed it truly was only human. Some have argued that jealousy, with its focus on social threat, requires a concept of “self” and a theory of mind.

Anyone who's had a dog as a pet knows that dogs feel jealousy. We don't need to look at any studies. It's clearly the case that a dog doesn't have to have a concept of self, it just has to know that another animal is receiving affection and it isn't. Apparently, people are "anthropomorphising" in assigning emotions to animals. That's right, we are! If an animal behaves in a very similar manner to a human being who's in a certain emotional state, it is rational to assign that emotional state to the animal too. Any sane person would, but unfortunately many scientists have a propensity to believe the most preposterous stuff imaginable.