The large intestine of an elephant is 10 times longer than a cat, but their defecation time is almost identical: an average of 12 seconds. This counterintuitive paradox not only confuses you, it also annoys scientists at the Georgia Institute of Technology.

"*How can all animals defecate in a constant time?*"They seriously asked this question in an article published in Soft Matter magazine."*To answer this question, we have to start from analyzing their droppings. "*

So let's see how they decipher the mystery.

The large intestine of an elephant is 10 times longer than a cat, but their defecation time is almost identical.

Like any scientific problem, researchers must begin to determine in which variables. The moment when the defecation process of an animal begins to occur, is called t = 0. Scientists define it as a time "*The head of the stool is sticking out*".

To simplify the problem, they do not consider the defecation processes of rabbits, in which they create small pellets. Researchers only consider defecation in which cylindrical and continuous stool is like what humans usually do with a healthy digestive tract.

The next variable is how long each litter is? They default to the length of the rectum. But not only that, stool has mucus, and another variable to be included is mucus.

These are indispensable lubricants for intestinal peristalsis. Mucus has a certain thickness and viscosity, both are quantified by researchers and included in the problem.

A mouse has only a thin layer of mucus inside its rectum, and an elephant needs a thicker layer of mucus, as you can imagine.

And to push the stool out of the gastrointestinal tract, it requires a significant pressure on your rectum.

See, you may not realize this, but the diameter of your stool is in line with the diameter of the rectum, implying that the stool doesn't stick out like you squeeze a tube of toothpaste, but it slides out like like children or playing slide.

Regardless of their size or size, the animals rhyme almost defecate at the same time

After setting all the variables involved in defecation, scientists filmed more than 30 videos in which animals at the zoo addressed their sadness. Combined with that, variables are included in a mathematical simulation that runs on the computer with the equation:

The seven-variable equation and some fractional exponents with T are defecation time, L is the length of the stool, h is the thickness of the mucous layer in the intestinal wall, D is the diameter of the stool, P is the pressure of the stool colon, n and K are two other properties of mucus.

It looks troublesome but "*cultural*"It is like this: The time required for a defecation is equal to the length of the block divided by its velocity.

Gravity is eliminated from the equation, because most mammals have horizontal rectum, so the weight of the stool does not have a great effect.

Larger animals can produce larger stools, but they also exert more force on those feces and have more mucus to help them slide along the rectum outward.

The result is that the time that they defecate is almost the same, averaging 12 seconds with an error of 7. There are 66% of the animals in the study have defecation time of 5-19 seconds, including those dogs with a weight of 10 ml and whales with a volume of up to 20 liters.

It turns out that the parameters of mucus and peristalsis balance these differences. For example, it allows an elephant to defecate at 6 cm / sec, which is 6 times faster than a dog. The rate of human toileting is about 2 cm / sec.

The average defecation time of animals is 12 seconds

Of course, these are average numbers. In many other problems, simulation variables can give different results. For example, when a person has diarrhea, the human gastrointestinal tract does not even need to create pressure. Feces can then flow in the direction of gravity.

But the equation for the time of diarrhea involves slightly different variables, because it "x*It happened so fast that a steady state was not reached*"Scientists estimate that a person weighing 70 kg has diarrhea, the defecation time lasts only 0.5 seconds according to the equation:

On the other hand, running this math simulation for constipation means eliminating the effect of mucus. With zero and "variable*hardest stool*", the maximum pressure put on the rectum must also take you 6 hours to defecate:

Fortunately, if there is participation in intestinal wall deformity, the time of constipation can be reduced in practice.

Back to normal, you may need to count when you go to the bathroom later. If the number is 12 at the time you are "*finish*", that is a sign that your gut is healthy.

But you may ask that "*Why do I have to count?*"And why do they, scientists, have such an odd study?

Let's count down 12 seconds!

Back in 2015, it was the research group at Georgia Institute of Technology that won the Ig Nobel Prize for its work to identify all mammals that urinate within a 21-second period. This makes them continue to want to investigate defecation activity to thicken the collection.

But studies of excretion and digestion of animals and humans are not in vain. In fact, gastrointestinal health is also an important part of your overall health. Defecation, urination and defecation are all signs that your body is functioning properly.

Knowing what is a normal number may indicate an abnormality. Just ask a patient who has just removed the appendix. During recovery after surgery, doctors said they should eat certain foods, walk around and then report their defecation.

The doctor will ask if you can deflect, and if you have defecation. The best answer should be yes. Sometimes some patients answer dishonestly, doctors also have to ask them to fart under their witness.

Similarly, defecation also provides a more concrete evidence, saying that your digestive tract is active. And if the digestive tract works well, from the moment you "*act*"In the toilet until the end, the number should be 12 seconds.

Refer *Popsci, Science, Softmatter*