Dog lovers know that dogs get jealous. A new study shows this is true. A university conducted research into dogs and jealousy. The research came after a professor saw her parents' three dogs behaving strangely. When she stroked them, they became aggressive towards each other. They tried to knock her hand away so they could get "exclusive attention". She said: "That got me to thinking about jealousy in dogs."

Researchers used a children's jealousy test on 36 different dogs and recorded their reactions. The dogs' owner read from a book while petting a toy dog and a Halloween lantern. The researchers wanted to see if the dogs were jealous of the toy dog and lantern. They found that the dogs were twice more jealous of the toy dog. The researcher wants to understand more about jealousy. It is a leading cause of murders around the world.