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Jason English
Jason English

Is a Dog's Mouth Really Cleaner Than a Human's?

Jason English
Jason English

Comparing a dog's mouth with a human's mouth is sort of like comparing apples and oranges—really filthy apples and really filthy oranges. Both species' mouths are hot, damp places teeming with roughly equal populations of bacteria. Neither would be described as clean, and any question of comparative cleanliness is irrelevant because so much of that bacteria is species-specific. Most of the germs in your dog's mouth aren't going to be a problem during a big, wet doggie kiss. You're more likely to run into trouble kissing another human than you are a dog, because bacteria from a person's mouth will feel equally at home in yours.

bailey-mouth

Of course, not all bacteria are species-specific. Dogs and humans can and do transmit some germs to each other via the mouth, so if your dog is the type that likes to lick faces (is there any other type?), there are a few precautions you can take. One, try to keep your dogs from picking up any external bacteria by keeping them out of the trashcan (and away from rancid food), and away from wild animals (lest they contract rabies). Two, keep them healthy: up-to-date vaccines, good external and internal parasite control, regular teeth brushing, etc.

And then, pucker up!

While we're at it, let's tackle two more things we're often told about canines: 1) Dogs lick their wounds and they heal very fast, and 2) Dogs don't get as many cavities as humans. There are simple explanations for both. Licking the wounds gets rid of dead cells and dirt, just like when we wash our wounds. The immune system takes it from there.

As for cavities, they're largely caused by the bacteria Streptococcus mutans. These bacteria feed on sugar, which is far more common in a human's diet than a dog's. Hence S. mutans prefers to live in our mouths, not Fido's.

[This Big Question originally appeared in 2010.]

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Big Questions
Why Does Turkey Make You Tired?
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Why do people have such a hard time staying awake after Thanksgiving dinner? Most people blame tryptophan, but that's not really the main culprit. And what is tryptophan, anyway?

Tryptophan is an amino acid that the body uses in the processes of making vitamin B3 and serotonin, a neurotransmitter that helps regulate sleep. It can't be produced by our bodies, so we need to get it through our diet. From which foods, exactly? Turkey, of course, but also other meats, chocolate, bananas, mangoes, dairy products, eggs, chickpeas, peanuts, and a slew of other foods. Some of these foods, like cheddar cheese, have more tryptophan per gram than turkey. Tryptophan doesn't have much of an impact unless it's taken on an empty stomach and in an amount larger than what we're getting from our drumstick. So why does turkey get the rap as a one-way ticket to a nap?

The urge to snooze is more the fault of the average Thanksgiving meal and all the food and booze that go with it. Here are a few things that play into the nap factor:

Fats: That turkey skin is delicious, but fats take a lot of energy to digest, so the body redirects blood to the digestive system. Reduced blood flow in the rest of the body means reduced energy.

Alcohol: What Homer Simpson called the cause of—and solution to—all of life's problems is also a central nervous system depressant.

Overeating: Same deal as fats. It takes a lot of energy to digest a big feast (the average Thanksgiving meal contains 3000 calories and 229 grams of fat), so blood is sent to the digestive process system, leaving the brain a little tired.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

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How Are Balloons Chosen for the Macy's Thanksgiving Day Parade?
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Getty Images

The balloons for this year's Macy’s Thanksgiving Day Parade range from the classics like Charlie Brown to more modern characters who have debuted in the past few years, including The Elf On The Shelf. New to the parade this year are Olaf from Disney's Frozen and Chase from Paw Patrol. But how does the retail giant choose which characters will appear in the lineup?

Balloon characters are chosen in different ways. For example, in 2011, Macy’s requested B. Boy after parade organizers saw the Tim Burton retrospective at the Museum of Modern Art. (The company had been adding a series of art balloons to the parade lineup since 2005, which it called the Blue Sky Gallery.) When it comes to commercial balloons, though, it appears to be all about the Benjamins.

First-time balloons cost at least $190,000—this covers admission into the parade and the cost of balloon construction. After the initial year, companies can expect to pay Macy’s about $90,000 to get a character into the parade lineup. If you consider that the balloons are out for only an hour or so, that’s about $1500 a minute.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

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