A literature review carried out by researchers at the University of Exeter has reached a conclusion that may upset millions of pet owners: the combination of many different studies of animal intelligence suggest that dogs are no smarter than many other animals. You may think your pooch understands every word you say, you may believe that Rover knows exactly what is going on around him, and you may like to think that when he looks at you with his head cocked, that he has the intellectual ability of a super-smart mammal. The truth? He may be no smarter than a pigeon.

In fairness, the review started by stating that a comparative analysis to rank the intelligence of different animals is almost an impossible task. There are over five thousand species of mammals, eight thousand species of birds, ten thousand reptiles, thirty thousand fish, and innumerable invertebrates like ticks, fleas and spiders. What tests would you use to compare how smart one creature with another? They live such different lives, and have such a wide range of different skills. How do you define intelligence anyway? A spider could be highly skilled at telling the difference between a speck of dirt and a dead insect caught in their web. Does that make them clever?
The researchers did not give up easily: to make it easier to rank the intelligence of dogs, they narrowed the field. They decided to only compare dogs with three similar types of animals. Medium sized carnivores (e.g. wolves), those that hunt in packs (African wild dogs, dolphins and chimpanzees), and other domesticated animals (cats, pigs, goats, pigeons and horses).
Then they chose areas of “intelligence” that could be compared.
First, sensory cognition: smell, hearing, taste, and touch. Dogs performed adequately: better at taste than cats, but worse at the sense of touch (think of a cat’s sensitive whiskers). Overall, dogs ranked similarly to other animals, and not outstandingly better.
Second, physical cognition, defined as the ability to interact with the surrounding environment. This included puzzles, like pulling strings to grab a treat behind a screen, opening boxes to retrieve hidden treats, and working out how to move objects out the way to get rewarded. Their conclusion was that while dogs can learn to repeat tasks, they aren’t so good at working out the answers from first principles.
Third, spatial cognition; this involves on-the-ground geography. Dogs can be particularly good at remembering places (e.g. they may recall where they buried a bone many months later) but they are not good at working out simple navigational tasks (such as walking around a wall to get to an owner calling them from the other side). Overall, dogs could be said to be a bit slow in this regard, even compared to simpler creatures like pigeons (who have astonishing navigational skills).
Fourth, social cognition. This assessed response to gestures (like pointing) and facial expressions, as well as cooperating with fellow pack members and learning by watching other animals. As you’d expect from the way that dogs have evolved to live in social groups with other dogs and with humans, dogs did well in this area compared to other creatures (such as independent-minded cats who really don’t seem to care what other animals – or humans- do.)
The final area of intelligence to be assessed with perhaps the most telling: “consciousness of “self”. Does a dog know that it is a dog? You clearly can’t interview a dog to find out, so the Mirror Mark Test is used. Under anaesthesia, a visible mark (like an ink spot) is placed on the animal, somewhere that they can’s see (such as the forehead). When they wake up, they are placed in front of a mirror. Humans, chimpanzees, dolphins, magpies and even ants recognise that the image represents themselves, and they try to touch the spot. Most other species- including dogs – do not. This lack of ability represents a serious smartness-deficit.
So what did the overall comparative review conclude? Our canine friends are not nearly as clever as chimpanzees or dolphins. They rank in a similar way to cats, goats and pigs. And depressingly, in some ways, they aren’t as smart as birds like pigeons and magpies.
My take on this is that dogs are brilliant at being dogs: they have evolved to excel in the skills – physical and intellectual – that they need to possess to do what dogs have to do. And it’s rather a silly exercise to try to compare them with animals that have different niches in the global ecosystem: only creatures with wonky intellectual abilities – like humans – would try to make that assessment.
There is another take home point, however: if pigs are smarter than dogs (which was one of the findings of the review), why do we think it’s acceptable to cram them into concrete pens with nothing to do, while we accept that dogs need to be kept in enriched, social environments?
Rather than worrying about frivolous questions like how smart our pets are, wouldn’t we be better to use our own intellectual ability to reflect on our irrational institutional abuse of other species that have far more intelligence than we give them credit for?