WASHINGTON — Dogs are considered man’s best friend, but a new study indicates that many dogs want to be man’s only best friend.

Dogs can feel a basic form of jealousy, according to a study from the University of California, San Diego published Wednesday.

Researchers taped 36 dogs’ reactions when their owners ignored them and did other tasks. The tasks included giving affection to a plastic jack-o-lantern, showering an animated, stuffed dog with love and reading aloud a children’s book that had pop-up pages and played melodies.

About 80 percent of the dogs pushed or touched their owners when they were affectionate with the life-like toy. Also, about 25 percent of the dogs tried to get in between the stuffed animal and the owner, or growled at it.

While the dogs seemed less jealous of the plastic jack-o-lantern, 40 percent of the dogs acted aggressive toward it when owners gave it the attention. About 20 percent of the dogs pushed or touched their owners during the book-reading time.

The research supports the view that “there is a primordial form of jealousy,” according to the study.

“We can’t really speak to the dog’s subjective experiences, of course, but it looks as though they were motivated to protect an important social relationship,” Christine Harris, University of California, San Diego psychologist and an author of the study said to Reuters.

Researchers say primordial jealousy exists with human infants. Several studies have found that infants as young as 6 months old can display behavior similar to jealousy when their mother interact with other infants.

The researchers say dogs may have developed jealousy as a results of their long domestication by humans.

“Perhaps this is a function of their emotional bonding with humans along with their motivation and ability to track human gaze/attention,” the study says. “Humans, afterall, have been rich resource providers over our coevolution.”

The study was published Wednesday in PLOS ONE.

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