The Nose Knows: I've always assumed a dog's sniffer worked the same way a human's schnoz did. That is, we take air (scents) in, expel it, then take in some more. But that's not quite the case. According to Horowitz, a dog's nose is built to allow a continual passage of air over the scent receptors. As inhaled air escapes through the slits of the nose it creates a vacuum that pulls in more air. In other words, a dog never loses touch with the scent as air is flowing inward at all times. For a dog, the world of scent can be compared to our world of vision. Imagine that they see the world in scents. Pretty cool.
Color:** I've always heard that dogs are color blind. Not so, says Horowitz. But they do see colors a bit differently than we do. Yellow, red, and orange don't look that way to your pup. Red resembles a faint green. Remember this when you want pup to use her nose when retrieving a dummy. Toss a red/orange dummy into a field of green grass and it will be camouflaged in its surroundings. (But only do this after pup is rock-solid on retrieving. Don't make early retrieves tough.)