When dogs roll over onto their backs and expose their bellies, their behavior is a sign of submission, right? Well, new research suggests that we may be interpreting canine body language all wrong.
A new study by researchers at the University of Lethbridge in Canada and the University of South Africa shows that rolling over may be more of a combat maneuver than an act of submission.
For the study, the researchers observed a medium-sized female dog as she played one at a time with 33 different dogs. They also analyzed 20 YouTube videos showing dogs at play--examining each time a dog rolled over onto its back.
What did the researchers find? None of the rollovers observed in the study were consistent with submission. Instead, the rollovers appeared to be used as defensive tactics to avoid neck bites or offensive maneuvers to launch an attack.
"We were very surprised that not a single instance of turning to supine in our sample of dogs could be attributed to submission," study co-author Dr. Sergio Pellis, a professor of neuroscience at the University of Lethbridge, told The Huffington Post in an email. "This strongly suggests that other studies that have used the supine posture as an indicator of submission may have exaggerated the role of dominance relationships in regulating the social behavior of domestic dogs in general and the relevance of dominance relationships during play in particular."
In other words, rolling over isn't always about dominance and submission. After all, the researchers explained that if rollovers were used as submissive gestures in play, then the smaller or weaker dog would be more likely to roll over--but in their observations the researchers noticed that the bigger dog was more likely to roll over.
The researchers also pointed out that if a rollover were being used as a submissive gesture, the dog would hold that position for a longer amount of time--but the rollovers they observed tended to be brief.
As for why we've been wrong about rollovers, Pellis pointed to previous research on wolves. In wolf packs, animals of inferior status do tend to roll over onto their backs as a submissive gesture, but that occurs mostly in non-play contexts.
"Even though dogs may have originated from wolves, their behavior is highly divergent," Pellis said in the email. "To further understand dog behavior, then, requires that we carefully examine the capabilities of dogs within the context of their current environment as partners to humans."
The study was published in the Jan. 2015 edition of the journal Behavioural Processes.