All pets can be jealous at one point depending on how they are treated and what's happening at the moment. They can even get jealous over human beings and not only their fellow pets. 

From series of videos that I have watched online, I can see that dogs are jealous animals. They don't like to share their owners with anybody. They are loyal too and I believe that they don't want trespassers around.

Any human being that loves you will always feel jealous when they are not getting enough attention from you. It's exactly the same thing with dogs too because they have emotions.