Ever noticed the little vertical groove running down the center of a dog’s nose, connecting the tip of the nose to the upper lip? This narrow groove has a name: the philtrum, which is also the word for the vertical groove that stretches from the base of the nose to the upper lip on human faces.

Human philtrums develop in the womb as the face forms, but they have no known function. For our furry friends, though, the philtrum serves an important and fascinating biological purpose. Every time a dog licks its lips or nose — which they tend to do quite a lot — a small amount of saliva collects in this narrow channel. 

In 1989, a Labrador Retriever named Max single-handedly flew a light aircraft from London to Paris.

fact

FIB

Ready to reveal?

Confirm your email to play the next question?

sign up!

Please enter valid email.

Sign up

Oops, incorrect!

It's a fib

No dog has ever piloted a plane all the way from London to Paris, but a British rescue dog named Shadow did learn how to fly a light aircraft, successfully completing a (deliberate) figure-eight maneuver at 3,000 feet in 2016.

Through a process called capillarization or capillary action (the same process that allows water to climb up the roots and stalks of plants), the saliva is gently moved up toward the nose pad, aka the leathery skin at the very tip of a dog’s muzzle. This helps keep a pup’s nose nice and moist — because a wet snout is much better at capturing scent molecules from the air. 

The moisture helps to trap, dissolve, and hold onto odor particles so a dog’s 300 million or so olfactory receptors can efficiently analyze all the wonderful smells that permeate its environment. So when your very good boy or girl gives you a big kiss and immediately licks their nose, they’re not just being adorable — they’re instinctively topping up the moisture in their philtrum so they can better understand the invisible world of smells around them. 

• Share to Facebook
• Share to Twitter
• Share to Email

Physicist Amos E. Dolbear is known for his work on early telephones and other inventions, but an 1897 issue of The American Naturalist contained a different type of scientific contribution: the hypothesis that cricket chirps are linked to air temperature. Dolbear’s observations (likely of snowy tree crickets, or Oecanthus fultoni) led him to theorize that the frequency of their chirps increased with warmer weather, and slowed as the thermometer fell. Surely, the phenomenon could be used to “easily compute the temperature when the number of chirps per minute is known,” Dolbear wrote. Most entomologists now agree that his theory — called Dolbear’s Law — is pretty spot-on, thanks to how insects respond to environmental changes. As cold-blooded creatures, crickets are unable to regulate their body temperatures internally, relying on the sun’s heat to fuel their metabolisms and provide the energy they need. Warmer temperatures allow the six-legged critters to use more energy, allowing more of the chemical reactions in their bodies that produce muscle contractions (and thus chirps) to occur — which we hear in the form of faster-paced songs. 

The earliest known insects couldn’t hear.

fact

FIB

Ready to reveal?

Confirm your email to play the next question?

sign up!

Please enter valid email.

Sign up

Oops, incorrect!

It's a fact

Some scientists believe the first prehistoric bugs were actually deaf. Some species evolved unique hearing organs over the past 400 million years — take the bladder grasshoppers’ abdomen ears or praying mantis’ lone chest ear — but others, like ants and beetles, remain unhearing.

You can easily test Dolbear’s Law on the next warm, buzzing night. Tune in to one cricket’s song, count the number of chirps you hear in 15 seconds, and add 37 for an approximate forecast in degrees Fahrenheit. (If math isn’t your strong suit, the U.S. National Weather Service has a handy cricket chirp converter that also provides a Celsius conversion). There are some limitations to using a cricket temperature gauge, however: Most crickets won’t sing when temps dip below 55 degrees or when heat pushes the thermometer past 100. And while many crickets respond to temperature shifts this way, not all chirp at the same rate. Fortunately, the snowy tree cricket is widespread throughout the United States — where, perhaps unsurprisingly, it’s also known as the thermometer cricket.

• Share to Facebook
• Share to Twitter
• Share to Email

The Swiss are known for their historic commitment to neutrality, but they’ve taken a firm stand on one of the most important issues of our time: guinea pigs. Because guinea pigs are social creatures who grow lonesome without a friend, it’s illegal to own just one of them in Switzerland. The law was introduced in 2008 as part of a legislative effort to grant social rights to pets. Should one guinea pig depart this mortal coil and leave its companion alone — and its owner in potential legal trouble — rent-a-guinea-pig services have emerged as a temporary solution.

Guinea pigs are named after the country.

fact

FIB

Ready to reveal?

Confirm your email to play the next question?

sign up!

Please enter valid email.

Sign up

Oops, incorrect!

It's a fib

Guinea pigs are native to South America, thousands of miles away from the African country. Some believe the name can be traced back to the cost of buying one in 17th-century England — one guinea coin — while others think it’s based on the Guianas, a region of South America.

Guinea pigs aren’t the only pets afforded special status in Switzerland. Goldfish are also prohibited from being kept alone, cats must at least have access to a window where they can see their fellow felines prowling around, and, for a time, dog owners were required to take an obligatory training course with their pooch (although that law was repealed in 2016). For all this, Switzerland doesn’t have an official national animal — though both the country and the Alps in general are strongly associated with cows and St. Bernards.

• Share to Facebook
• Share to Twitter
• Share to Email