Jealousy was once considered a strictly human emotion, but some people think dogs feel it, too.
A study published in April in the journal Psychological Science wanted to test how dogs display jealous behavior. First, each dog watched their owner next to a fake dog. Next, a barrier blocked the dog’s view of the fake dog while the owner appeared to pet the pretend dog.
Even when the dogs couldn’t see the rival dog, they displayed jealous behavior (forcefully attempted to reach their owner), which indicated they were acting jealously over an imagined scenario, something that’s never been demonstrated before.