The foot is one of the most overworked, under-appreciated parts of the human body. Think about it: In a single day, the average person takes 8000 to 10,000 steps. That works out to be four trips around the world over a lifetime. The foot may be humble, but its design is essential to how we walk upright, and hoofing it on two feet is a defining feature of humanity. Here are some fun—and a few funky—facts about the human foot.
1. OUR FEET ARE HOME TO ABOUT A QUARTER OF ALL THE BONES IN OUR BODIES.
There are 26 bones in each foot—one less than in each hand. When we’re born, those bones are mostly cartilage. The bones in our feet only completely harden around age 21.
2. HUMANS HAVE WORN SHOES FOR A VERY LONG TIME.
When did humans begin wearing shoes, anyway? About 40,000 years ago, according to research from Washington University in St. Louis that analyzed foot bones from Neanderthals and early humans. Older specimens had thicker, stronger toes, likely from gripping the ground as they walked barefoot. That’s around the same time that the archaeological record shows a plethora of artistic and technological advancements among early humans, including the first stone tools, which may have aided in the production of shoes. The oldest preserved shoe, incidentally, is 5500 years old and was found in an Armenian cave, buried in sheep dung.
3. THE BIG TOE USED TO BE A KIND OF FOOT THUMB.
This grasping toe helped our predecessors climb trees and, when young, grip onto their mothers. Thanks to modern science, if you lose your thumb, you can now replace it with a toe: toe-to-thumb transplants are a surprisingly common procedure these days.
4. THE FOOT HOLDS BIG CLUES ABOUT THE EVOLUTION OF BIPEDALISM.
Scientists are studying Homo naledi, a specimen discovered in a South African cave in 2013 that many researchers believe is a new human relative. H. naledi had very human-like feet, but with somewhat curved toe bones that suggest it climbed trees. It could be that H. naledi was beginning to experiment with walking.
5. THERE WAS A FOOT CHEESE EXHIBITION IN IRELAND.
Warm, sweaty feet make a perfect home for bacteria, which feed on our dead skin cells and produce gases and acids that emit those arresting foot odors. They're apparently also good at cultivating cheese. An exhibition in Dublin in 2013 displayed a variety of cheeses made with bacteria samples obtained from real people’s feet, armpits, and belly buttons. Delicious. We are relieved to know that no one actually ate any of the cheeses.
6. FEET ARE ONE OF THE MOST TICKLISH PARTS OF THE BODY.
There’s a good reason for that: Humans have nearly 8000 nerves in our feet and a large number of nerve endings near the skin. Having ticklish feet can be a good sign: reduced sensitivity can be an indicator of neuropathy.
7. THEY CAUSE BIG PROBLEMS FOR DIABETICS.
Complications of diabetes include poor circulation and nerve damage that can lead to serious skin ulcers, which sometimes require amputation of toes or feet. In 2010 alone, 73,000 lower-limb amputations were performed on diabetics.
8. FOOT SIZES AND WIDTHS IN THE U.S. AND UK ARE INCREASING.
Feet are spreading to support extra weight as our populations pack on the pounds. According to a 2014 study by the College of Podiatry in the UK, the average foot has increased two sizes since the 1970s. As people have grown taller and heavier, feet respond by growing. It appears many people are still in denial about their expanding feet, though: Though retailers are starting to respond by making larger and roomier shoes, half of women and a third of men reported they buy poorly fitting shoes. Podiatrists say ill-fitting shoes are to blame for a significant portion of foot problems, especially among women.
9. FORGET BARBIE'S TINY TOES. MANY GLAMOROUS WOMEN HAVE BIG FEET.
What’s with idealizing tiny feet for women, anyway? From the bound feet of female Chinese elites to Cinderella and Barbie, freakishly small feet are often celebrated as more feminine. But plenty of glamorous women both past and present have had larger than average feet, among them Jacqueline Kennedy, Oprah Winfrey, Uma Thurman, and Audrey Hepburn (size 10, 11, 11, and 10.5, respectively).
10. WOMEN HAVE FOUR TIMES AS MANY FOOT PROBLEMS AS MEN.
That painful fact is often attributed to wearing heels. Ironically, Western women started wearing heels to effect a more masculine look: European men adopted the look from Persian warriors in the 17th century, and women soon followed suit.
11. THE AVERAGE PERSON WALKS ABOUT 100,000 MILES IN A LIFETIME.
That’s a lot of stress on our feet. It’s not surprising, then, that lower back pain, headaches, indigestion and spine misalignment are often related to foot problems. Some runners blow way past this mark: They've logged at least 100,000 in running miles alone. One committed runner, Herb Fred, has run a whopping 247,142 miles.
12. FOOT SIZE HAS ZERO TO DO WITH PENIS SIZE.
In a study published earlier this year, researchers synthesized data from 17 previous studies that included the penis measurements of more than 15,000 men from around the world. The results: There is little evidence that penis size is linked to height, body mass, or shoe size. You can stop flaunting your size 13s, gentlemen.
13. THERE'S A REASON GRANDPA'S TOENAILS LOOK LIKE THAT.
Ever heard someone describing their toenails as “horse hooves”? As we get older, our toenails tend to thicken, making them hard to trim. This happens because toenails grow more slowly as we age, causing the nail cells to accumulate. Stubbing toes, bad shoes, and dropping things on your feet can also cause thickening, as can fungal infections and peripheral arterial disease, which narrows arteries and reduces the blood flow to limbs.
14. THERE'S A GUINNESS WORLD RECORD FOR MOST FEET AND ARMPITS SNIFFED.
Finally, reflect for a moment on grateful you are for your job. Because odds are you don’t have any tasks nearly as revolting as this one: In the 15 years that Madeline Albrecht worked for an Ohio lab that tests Dr. Scholl products, she sniffed more than 5600 feet and untold numbers of armpits. Albrecht currently holds the Guinness World Record for—yes, this is a category—the number of feet and armpits sniffed.