You're not imagining that sad look on Fido's face: A new study suggests that dogs might experience jealousy.
A new study from the University of California, San Diego, published Wednesday in the journal PLOS One, tested dogs to see if they exhibited jealous behaviors.
Researchers videotaped 36 dogs and watched their reactions to their owners playing with stuffed dogs, playing with plastic jack-o-lantern pails, or reading. The dogs reacted strongly when owners interacted with the stuffed animals, indicating a jealousy-like reaction for attention given to other "dogs."
More than three-quarters of the dogs pushed or touched their owners while they played with the stuffed dogs, and many growled at the stuffed animals. Only 40 percent became aggressive when their owners played with the plastic pails.
"It's clearly not just the loss of attention that triggered aggressive behavior," Christine Harris, lead author of the study, told Time. "It's that the owners were paying attention to another doglike object."
The study suggests that jealousy-like reactions can occur in animal species, such as dogs, in addition to human infants, as has been previously researched.