Asked by: Anonymous
The answer may be simple. There are good reasons why so many animals have two eyes, even though some spiders and insects have more. Two eyes on opposite sides of the head, as in many animals and birds, cover a wide angle. Two eyes facing the same way allow for binocular vision, which combines images from both eyes to judge distance. It may even be useful to have a spare – as I know from my poor kitten who pierced an eye with something sharp and had to have it removed but is now running about happily.
As for noses, there would no advantage in having two. The best place for taking in air and detecting smells is at the very front of the animal. Place one nose and two eyes at the front and there you have it!