Why do people wipe their butts but animals don’t

This day, you rushed to the bathroom in a hurry and suddenly realized that you forgot to bring paper. In your desperation, your cat walks gracefully into the bathroom with sarcasm written all over her face.

You are squatting on the toilet, feeling the coolness of your buttocks while feeling indignant: Why do people have to wipe their buttocks when they poop, but animals don’t?

The cost of wiping ass and walking upright

The first thing to correct is that animals aren’t completely immune to butts either.

In the case of your cat, 10% of its life is spent “cleaning” itself. Its tongue is covered with numerous papillae thorns. When cats lick various parts of the body, they are like small combs to comb out the dirt and parasites from the body[1][2].

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Cats have small barbs on their tongues to help them cleanse

As for why people wipe their butts, it may be traced back millions of years ago, when our ancestors began to learn to walk on two legs, realizing the transition from ape to man.

Walking upright frees both hands, giving human beings a stronger survivability and the possibility of multiplying in a wider field[3], but the gift of fate has long been a secret bid Well the price.

Because the spine becomes the load-bearing device for the head, upper limbs and trunk, long-term compression can easily damage your lumbar disc and cause back pain. At the same time, the lower limbs also bear more pressure, making you suffer from foot pain and knee injury [4].

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Upright walking is considered one of the hallmarks of human emergence

Similarly, pooping is one of the costs of walking upright.

In order to maintain the stability of the body and prevent falling forward, humans have developed strong gluteus maximus muscles that wrap the buttocks, and the anus located in the midline of the buttocks is hidden. When pooping, excrement is more likely to remain on the buttocks[5][6].

Long-term dirt residue, coupled with a relatively closed environment, provides a breeding ground for bacteria and aggravates the symptoms of anorectal diseases such as hemorrhoids [7]. So, your need to wipe your ass is really for health reasons.

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Actually, anal cleaning is no less important than washing your face

In contrast, animals that walk on all fours have no such annoyance. Because of their angled torso and legs, the hips are in the corners[6], and the anus is unobstructed, it’s clean and easy to pass through and ventilated after a bowel movement.

But the fact that I have to admit is that walking upright does give us flexible hands, and it is easy for us to use tools to wipe our buttocks.

Poop, their treasure

In addition, another reason why animals do not need to wipe their butts is that human beings, as higher creatures, have no special needs for feces, and for some animals, these excreted Feces may be a “treasure” for survival.

Hippopotamuses, for example, protect their territory by wagging their tails quickly when defecating, sending the feces out of the way [8].

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About 4,000 hippos excrete 8.5 tons per day

And some small and medium-sized herbivorous mammals treat “feces” as “everyday food”. In the case of rabbits, it produces soft stools during the day, swallows them quickly through the anus, and releases harder stools again at night. Since all soft stools are swallowed by rabbits, what you usually see are hard rabbit stools.

For rabbits, eats their own soft poop to grab more nutrients. The data show that the crude protein content in rabbit soft manure is 230-335g/kg, which can supply 15%-22% of the daily protein intake.

Also, soft stool protein is also rich in essential amino acids. Rabbits get 83% niacin, 100% riboflavin, 165% pantothenic acid and 42% vitamin B12 from soft stool.

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Coprophagy is a special digestive strategy for rabbits

Faces can also reduce hunger when food is scarce. Especially for rabbits surviving in the wild, life can be delayed for up to a week in the absence of water and food [9].

In contrast, as human beings, we no longer need to use feces to divide our territory, and it has become easier to grab food and nutrients. We eat four or five meals a day, milk tea, barbecue Adding hot pot has become a standard for many people.

Toilet paper, the lifesaver

It can be said that feces have become a symbol of uselessness and even filth to humans.

American scholars believe that the aversion to feces may reflect a human intuition about microorganisms, and this intuition reduces the probability of us ingesting pathogenic microorganisms [10].

But before toilet paper was invented, people struggled to get rid of this filth.

Due to different customs and climatic conditions, people use various natural materials for wiping, such as stones, shells, animal skins, etc. are all available tools[11].

In ancient Rome, a tool similar to a toilet brush was invented to wipe the buttocks. This tool consists of a stick and a sponge soaked in vinegar or salt water [11]. After each use, it is washed with water first, and then put into a vinegar bucket for disinfection, realizing the reuse [12].

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In ancient Rome, public toilets consisted of stone or marble slabs

The use of toilet paper in China actually predates the West by a large margin. At the beginning of the 14th century, Zhejiang alone produced 1 million bundles of toilet paper every year [13].

By contrast, Western countries did not have the first modern commercial toilet paper until 1857[14]. This toilet paper is made from Manila hemp paper and has a sheet-like structure [15]. Soaked in aloe vera juice, the toilet paper became softer, and its inventor, Joseph C. Guyty, even claimed that the toilet paper was effective in preventing hemorrhoids. As for the toilet paper roll as we know it, it was not mass-produced in the United States until 1890 [12].

Photo credit: Hagley Museum & Library

The toilet paper roll was first patented in 1871, and mass production began in 1890

Today’s toilet paper has been derived from cotton pulp, wood pulp, straw pulp and waste paper pulp and other production raw materials[16], it has become an indispensable and even crucial in our life. important part.

Data shows that in 2018, an American used an average of 141 rolls of toilet paper per year, while the average Chinese used 49 rolls of paper each year, weighing 4.4 kilograms[17].

No one can imagine what the world would be like without toilet paper.

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[1] Bradshaw, J. W. (2012). The behaviour of the domestic cat. Cabi.

[2] Eckstein, R. A., & Hart, B. L. (2000). The organization and control of grooming in cats.

Applied Animal Behaviour Science, 68(2), 131-140.

[3] Gao Lihong. (2018). The performance and origin hypothesis of upright walking in early humans. Biology Teaching (02), 71-72.

[4] Modern Express. (2010). Humans are a typical example of evolutionary failure. What will they look like in 500 million years?

[5] Jennifer Ackerman & Kali Wallinsky. (2006). Both are the fault of walking upright. China Geography (07), 152-171.< /p>

[6] Massive Science. (2020). How did human butts evolve to look that way?

[7] Sichuan Provincial Health Commission. (2021). Why do doctors say that “washing your butt” is more important than “washing your face”?

[8] CCTV. (2017). Unique enclosure method: Hippo spilling feces to protect territory.

[9] Chen Guiyin, Zhou Tao. (2004). Rabbit coprophagy and its research progress. Rabbit Rabbit in China (02).

[10] BBC. (2015). Why do we hate poop so much?

[11] Charlier, P., Brun, L., Prêtre, C., & Huynh-Charlier, I. (2012). Toilet hygiene in the classical era. BMJ, 345.

[12] Yangcheng Evening News. (2020). Funny story about cultural history: together day and night, do you know toilet paper?

[13] Smyth, R. (2012). Bum fodder: an absorbing history of toilet paper. Souvenir Press.

[14] National Graphic. (2020). What did people do before toilet paper?

[15] CNN. (2009). Why toilet paper belongs to America?

[16] Yicai.com. (2021). The “pulp” lake is in emergency! What does soaring paper prices mean?

[17] Statista. (2018). The U.S. Leads the World in Toilet Paper Consumption.


Author: Yang Weilai

Producers: Ta Gai, Feidi

Cover image source: Zhanku Hailuo