Animals can’t use language to speak to us, but that doesn’t mean they aren’t able to convey their thoughts and emotions. Body language and physical gestures are a powerful and often understated way in which complex life, from horses to bonobos, can communicate – and now, a new Animal Cognition study emphasizes that dogs are probably better at doing this than most of us appreciate.
The researchers – Dr Hannah Worsley and Dr Sean O’Hara from the University of Salford – are known for their work on dog-human communication. Their latest work is arguably the most groundbreaking: it reveals that our floofy companions can deploy 19 specific actions in order to let us know what they want.
They decided to look at referential gestures, which are – according to the paper – “used by a signaller to draw a recipient’s attention to a specific object, individual or event in the environment.” Think pointing, or nodding your head. Of course, these aren’t exclusive to humans; the researchers point out early on that other great apes have been “shown to possess impressive gestural repertoires.”
What about dogs, though? Well, their ability to use referential gestures has been somewhat evidenced by a few papers in the past. Dogs clearly are able to understand them, and certain actions are clearly designed to draw our attention to something – barking while repeatedly turning their head to face a desirable object, for example – but nothing more concrete or specific has been demonstrated.
In order to close this informational gap, 37 different male and female dogs were observed in their own homes using video recording equipment. Of a total of 47 potential referential gesture events, statistical analysis revealed that 19 of them were frequently used during everyday communicative attempts with humans.
All of these conform to the “five features of referentiality”: they are directed towards a specific thing, they are aimed at a recipient, they receive a voluntary response, they have no mechanical use, and they have the hallmarks of intent.
Here’s what they are, categorized by what they can potentially mean when intentionally performed. Some are more certain than others, so click here to see the table in full.
Requests: Scratch Me (A), Give Me Food/Drink (B), Open The Door (C), Get My Toy/Bone (D)
1 – Roll Over (A)
2 – Head Under (ABD)
3 – Head Forward (ABC)
4 – Hind Leg Stand (BCD)
5 – Head Turn (ABCD)
6 – Shuffle (A)
7 – Back Leg Up (A)
8 – Paw Hover (ABCD)
9 – Crawl Under (D)
10 – Flick Toy (B)
11 – Jump (BCD)
12 – Paw Reach (D)
13 – Nose (ABCD)
14 – Lick (ABCD)
15 – Front Paws On (ABCD)
16 – Paw Rest (AC)
17 – Head Rub (A)
18 – Chomp (A)
19 – Paw (D)
Of these, “head turn” was used to achieve all four requests; “paw hover” was used most often to ask for food or drink; “roll over” was always a request for a scratch; “head under”, or hiding the head, was predominantly used to ask for an object to be retrieved.
The researchers add that, should the original gesture not be acted on by the human, they can pick another to attempt the request again. Dogs who live with more people, and have lived with them longer, possess more gestures than other pups.
Describing the repertoire of gestures as “impressive”, the team also suggest that cross-species communication is theoretically more cognitively challenging than that within species. It’s been implied that great apes can do this because of their shared ancestry with humans, but dogs don’t have this apparent advantage and remain extraordinarily communicative regardless.