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Your Dog's Got Mail

Owning a dog is great fun, but it's also a ton of work. There's the feeding, brushing, washing, grooming, and, of course, the daily walks.

As you may have noticed, your dog probably treats each walk as an adventure-packed expedition through the Amazonian wilds. What's up with the constant sniffing of every patch of sidewalk, tuft of grass, and length of stop sign?

When dogs sniff so intently they're just doing what comes naturally. After all, a dog's sense of smell is vastly superior to ours. The average dog has around twenty-five times more smell receptors than humans and can detect smells at concentrations one hundred million times lower than humans can. The receptors, called ethmoidal cells, are packed deep inside a dog's snout, and when he takes a deep sniff its one whammy of a sensory experience. For example, dogs can detect a single drop of blood in five quarts of water. Some studies suggest that dogs can even detect the whiff of certain kinds of cancer.

It's not hard to understand why your dog gets so excited when he sniffs a spot recently urinated upon by a fellow canine. A dog's urine gives off a distinctive scent and is used to mark territory. It sends a message to other dogs: this is my turf! Of course, your dog is likely to respond to this urine-based graffiti by urinating on the same spot! Touch

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