Yesterday a story surfaced about authorities finding $3 million in cash on a bus bound for Mexico. How did they find such a large sum of money hiding on the bus? With a cash-sniffing dog. Wait, dogs can sniff out cash? Sure, they can. Since carrying giant sums of cash is often a good indication that chicanery is afoot, law enforcement agencies throughout the world use dogs to help catch couriers for drug, arms, and counterfeiting rings. Last December a single cocker spaniel found around a quarter of a million dollars worth of nefarious cash at Milan’s airport over just a two-day span.

Yes, dogs can find almost anything. Their noses contain far more olfactory receptors than humans’ sniffers do, and the receptors are situated perfectly along the main airstreams of the pups’ noses. Sure, you already knew that detection dogs were able to sniff out drugs, bombs, and corpses, but what else can a well-trained pooch find using only his nose?

1. DVDs

Take a walk in any major urban area, and it won’t be long before you run across someone peddling bootleg DVDs. These black-market discs hit the street market so quickly that they might even hit a city before a film gets a theatrical release there, so movie studios and theaters take huge losses when patrons buy a flick on the street instead of shelling out ten bucks for a ticket. That’s why in 2006 the film industry introduced the world to Lucky and Flo, the world’s first DVD-sniffing dogs.

A broad alliance of film groups including the MPAA and the Federation Against Copyright Theft fronted the cash so the two black Labrador retrievers could learn the unique smell of a polycarbonate disc. At first, the pair had some trouble when they started work at the FedEx hub at London’s Stansted Airport. A counterfeit DVD smells just like a legit one, so the dogs were alerting their handlers any time they found a package that had any DVD in it.

Gradually, though, they got the hang of finding the counterfeit loot. While on loan to the Malaysian and Philippine governments in 2007, Lucky and Flo uncovered 1.8 million counterfeit DVDs, a discovery that so enraged a Malaysian organized crime syndicate that the dogs allegedly had a $30,000 bounty on their heads. Luckily, they escaped unscathed and are still out there searching for bootlegged copies of Miss March.

2. Whether a Cow’s in Heat

There’s very little romance involved in commercial cattle breeding. For the most part, the cow is artificially inseminated, so the bull’s not even around to make awkward excuses about why it’s not going to call. Given this impersonal system, breeders need to know when the perfect time to inseminate the cow is, and dogs can help. Since a cow’s physical chemistry changes slightly when she’s in heat, a dog can sniff out the differences and alert a farmer that the time is right to open the door to the semen freezer. How good are dogs at telling when a cow’s in heat? According to a quote Professor Lawrence J. Myers of Auburn University gave the New York Times, the canines are even better at picking the right time than bulls are.

3. Insects

No one wants to buy a house, have it pass an inspection, and then find out the place is rife with termites, bedbugs, or another pest. Dogs can use their noses to help alleviate this problem. After extensive training that can run up to $15,000 per pooch, dogs can help homebuyers and pest control companies by sniffing around walls and baseboards to look for termites or bedbugs. Once a dog has found the offending insects, exterminators can take care of the problem, then bring their canine friend back in for a second pass to make sure the bugs are really gone. Here’s a video of a beagle on the job searching for bedbugs:

4. Cell Phones

We don’t ordinarily think of cell phones as the sort of menace that needs to be rooted out quickly and efficiently, but they’re a major headache for prison officials. Prisoners who have contraband phones can continue coordinating illegal activities from their cells, badger witnesses, and plot escapes. Thanks to their various uses, inmates tend to be pretty crafty with where they stow their phones. These hiding places might fool a human official, but a dog can sniff them out with ease. According to an October 2008 news story, Virginia and Maryland have been using phone-finding dogs in their prisons, and Florida recently debuted Razor, a young Malinois who can sniff out prisoners’ phones.

5. Cancer

This one’s still in its early stages, but many researchers are optimistic that a well-trained dog can detect cancer in humans. The basic logic is very similar to the cows-in-heat example; a cancerous cell might excrete chemicals that aren’t ordinarily found in the human body but can be detected by a dog. Theoretically, the dog could take a whiff of a person’s urine or breath and figure out if the patient had certain types of cancer. If the dogs could reliably make this diagnosis early on in a patient’s illness, physicians would be able to better manage the disease. Marine, a black lab from Japan, is thought to be particularly adept at sniffing out cancer, so last year scientists starting cloning her to create a larger army of cancer-smelling canines.