Predator species, like humans and dogs, have eyes set close together. Human eyes are set straight forward while dog eyes, depending on the breed, are usually set at a 20 degree angle. This angle increases the field of view and therefore increases the peripheral vision of the dog. Increased peripheral vision compromises the amount of binocular vision. Binocular vision occurs where the field of view of each eye overlaps.
Binocular vision is necessary for depth perception.
Dogs' depth perception is best when they look straight ahead. This is not an ideal situation as their nose often interferes. Predators need binocular vision as a survival tool. Binocular vision aids in jumping, leaping, catching, and many other activities fundamental to predators. In addition to having less binocular vision than humans have, dogs also have less visual acuity.