Cannabidiol (Cbd) Elicits Contagious Yawning in the Domestic Cat, a Non-Social Species Lacking Spontaneous Contagious Yawning

The current study investigates contagious yawning (whereby one individual’s yawn triggers another individual to yawn) in domestic cats, a non-social species and in domestic dogs, a social species. In several domesticated animals as well as in wild animals, these phenomena are known to occur. However, the reported cases are restricted to social species. In the current study, for the first time, the author tested whether contagious yawning occurred in response to their caregivers’ yawn in 40 cats (randomly divided into two groups) and 20 dogs. It was found that the cats did not yawn contagiously in response to human yawning, but this behaviour did occur in most of the dogs. Next, each of the two groups of the cats received the administration of cannabidiol (CBD), the primary non-addictive component of cannabis, at 4.0 mg/kg/day over a 2-week-period, or the administration of the same amount of sunflower oil as placebo (the CBD group and the Placebo group). When their responses to their caregivers’ yawning were tested again after the end of the administration, the number of yawning cats significantly increased in the CBD group, but not in the Placebo group. The results indicate that CBD could exert effects to elicit contagious yawning in domestic cats, non-social species. When CBD is administered, they become more susceptible to contagious yawning and consequently more likely to be triggered to yawn after viewing the yawn of their caregivers.