Much like their human counterparts, dogs use depth perception to navigate the world. Depth perception in dogs is not the same as in humans, although the basic visual functions remain the same. A dog’s depth perception is paramount to how he navigates his surroundings, and understanding how your dog’s depth perception works will help you forge a better relationship with your canine companion.
Depth perception, often referred to as depth sensation in animals, is the ability to see the world in three dimension and gauge the distance to a particular object. Dogs determine the distance to an object by using visual cues projected into a two-dimensional image in the retina. When a dog is looking at an object close to him, both eyes turn slightly inward toward the object in what is known as ocular convergence. When the dog is focused on a distant object, known as ocular divergence, each eye displays a slightly different angle, indicating that the object is farther away. Dogs have wider peripheral vision than humans, but they have weaker binocular vision and depth perception due to the wider placement of their eyes.
The accuracy of a dog’s depth perception is dependent on a number of factors, including breed and age. Breeds with wide set eyes, such as mastiffs and pugs, may have less accurate depth perception because their binocular vision field is smaller than breeds such as whippets, whose eyes sit closer together. A dog’s depth perception also is affected by the length of his muzzle. Dogs with a longer muzzle may have more difficulty with objects directly in front of him because his nose blocks his field of vision.
Depth perception may decrease as the dog ages, since the eyes are not able to focus as well as those of a younger dog. Even dogs with severe depth perception problems and blindness can lead happy, healthy lives as long as their owners are mindful and make slow, gradual changes to their surroundings. Walk slowly around dogs with failing vision to keep the dog calm and avoid startling him. If you own a dog with depth perception problems, do not move furniture often, but if you must rearrange, do it gradually to prevent the dog from running into things.
Once you understand how dogs views the world, you can begin to incorporate visual cues into your dog’s routine. Most dogs respond well to visuals, but they must be done slowly and in your dog’s line of sight. Dog trainers and handlers often give hand signals in addition to verbal cues to teach the dog to mind both in close proximity and at a distance. For example, to give your dog a visual cue for the “down” command, stand 3 or 4 feet in front of the dog and hold your right hand at your waist, with your palm facing the ground. Lower your hand slowly toward the ground as you tell the dog “down,” keeping your hand in line with the dog’s eyes. You can use hand signals to reinforce any verbal command you choose; as long as you are consistent and use the same signal each time you give a particular command, your dog will catch on.
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