I get to do a lot of radio and newspaper interviews about different news topics. Recently, I've done several interviews about dogs. "Dogs?" you ask. Yes, dogs. There is actually a good reason for this: Dogs are in the news all the time. Dogs find big drug shipments for the police, dogs dial telephones and save their owners, dogs cover 1,000 miles of mountainous terrain to return to their masters, etc. It's all good stuff for the news.

It turns out I know a lot about dogs. There was a point in my life where I lived on a farm and actually owned eight dogs at one time — I had my own pack. They were all mutts, most of them strays that just "showed up" looking for food (the farm was in the middle of nowhere and surrounded by woods). What I learned from that experience is that dogs are amazing animals.

In doing these recent interviews, I have been reminded of two dog facts that would be interesting to discuss.

SUPER SNIFFERS

Dogs do have amazing noses. They can smell scents that are far too dilute for humans to detect. They can also pick one smell apart from another, even if one of the scents is overpowering. For example, if you put marijuana in a heat-sealed plastic bag, and then wrap the bag in towels soaked in perfume, dogs can still smell the marijuana.

The thing that gives dogs their amazing sense of smell is a huge nasal patch. Humans have a nasal patch that is about as big as a postage stamp. It holds maybe 5 million smell cells (officially, they are called olfactory receptors). An olfactory receptor is a special nerve cell that can sense a certain kind of smell molecule. If one of those smell molecules attaches to the right receptor, the receptor fires and we smell something — a banana, a rose, a skunk or whatever.

Dogs blow us away when it comes to smell cells. The nasal patch of a dog is about the size of a dinner plate, all folded into the snout. They have more than 200 million receptors — maybe 50 times more than people do.

This gives dogs a huge advantage when it comes to smell. Not to mention the fact that a dog's nose is right where it needs to be on the end of the snout, and the snout is close to the ground. Dogs were designed to smell.

FATAL CHOCOLATE

What about chocolate? Why can people eat chocolate all day long, but if a dog eats chocolate it can die? That is actually true, by the way. A small dog that gets into a kid's Easter basket full of chocolate can actually die. What is going on there?

It turns out that, for dogs, a chemical in chocolate called theobromine is the source of the problem. Theobromine is like caffeine. People are fine eating theobromine (or caffeine) because we can metabolize these chemicals quickly. Dogs can't.

Different types of chocolate contain different amounts of theobromine: It would take 20 ounces of milk chocolate to kill a 20-pound dog, but only 2 ounces of baker's chocolate or 6 ounces of semisweet chocolate. It is not that hard to imagine a dog finding a chocolate bar sitting on the coffee table and gobbling it up. If the dog is small, that could be deadly.

The next time you see a dog, you can look at it with new respect for its sense of smell. But don't feed it any chocolate.

Marshall Brain is co-founder of www.HowStuffWorks.com.