Nature is a brutal place, so during breeding, the chinstrap and Adelie penguins are reluctant to leave their eggs unattended in the nest, even for relief. But you also don’t want to stain the nest with feces. Instead, a wistful penguin will duck, point its rear end away from the nest, lift its tail, and let a feces projectile fly, thus ensuring the safety of the eggs and the cleanliness of the nest.
In 2003, two intrepid physicists were fascinated by this behavior and were inspired to calculate the answer to a burning question: how much pressure can these penguins generate to propel their feces away from the edge of their nests? Answer: About three times more pressure than a human could produce. That newspaper earned them a 2005 Nobel Prize in Nobel and lasting glory among the penguin-obsessed he poops. Now, a couple of Japanese scientists have weighed in on the matter, calculating the projectile trajectory of the excreted feces and recalculating rectal pressure. These scientists reported their findings in a draft of the document they published in the physics arXiv.
According to Victor Benno Meyer-Rochow of the Japan Luminous Organisms Research Institute, co-author of the original 2003 article, all of these fecal findings began with an expedition that led to Antarctica. Although he was collecting samples of local marine worms and small land insects called springworms for further study, he also took copious photographs of the many penguins in the region, which he used in his lectures. During a seminar at the University of Kitasato in Japan, a young woman asked about a slide that showed a penguin brooding in its nest, wondering about the pink and white lines radiating outward. She interpreted them as “decoration” and asked how penguins made them.
“I explained that a penguin stands up, moves to the edge of its nest, turns around, lifts its tail, and then shoots from its rear, leaving a 30-40 cm long streak of off-white material. semi-liquid behind, “Meyer said -Rochow wrote in a 2019 blog post.” Everyone laughed, except for the interrogator. He turned red and sat quietly. ” (The color of the feces depends on the penguin’s diet: if it is mainly fish, the poop is white. If the penguin has feasted on krill, the poop turns pink.)
Meyer-Rochow argues that it was not a stupid question, particularly because it prompted him to take a closer look at his slides, among which he found several photographs capturing penguins in the middle of the poop. Measuring the length of the stripes that unfold from the nest was a fairly simple matter. Estimating the height above ground and the opening of the sewer, the opening through which penguins defecate, was equally simple. It also determined the “sticky” surface of penguin dung. With that information, Meyer-Rochow and his co-author, Jozsef Gal of Loránd Eötvös University in Hungary, were able to calculate the force it would take to propel the poop between 30 and 40 centimeters. They then used that figure to estimate how much pressure the penguins must exert to shoot their poop away from the nest.
The answer: Penguin internal pressures can reach 10 to 60 kilopascals (0.1 to 0.6 atmospheres, or 600 grams per square centimeter), significantly higher than the pressure that the average human can exert when defecating. Meyer-Rochow said the pressure was comparable to “at least half the tire pressure of our cars,” adding: “Not bad for a small companion one-third the size of a human.” However, the study did not address why stripes radiate from the nest in all directions without noticeable preference. Does this depend on the direction of the wind or does a penguin somehow “choose” where to dump his feces? That remains an unsolved question.
New shit has come to light
In this latest article, Hiroyuki Tajima from Kochi University and Fumiya Fujisawa from Katsurahama Aquarium in Kochi, Japan, point out that the original 2003 paper did not take into account the trajectory of the penguin feces projectile. Instead, it focused on a horizontal distance. Tajima and Fujisawa argue that the angle of expulsion is not always horizontal, especially if the breeding environment is in a higher location, or if the penguin is standing on a rock while defecating, for example.
Using Newton’s equations, they calculated that the maximum flight distance of the penguin droppings is 1.34 meters, or 4.39 feet. Tajima and Fujisawa also re-examined the question of the rectal pressure required to achieve such a trajectory and found that it would be slightly higher than the original estimate. However, they noted that their simplified equations did not explain the hydrodynamics of faeces in the air and in the stomach, “remaining for future work.”
As for why they decided to revisit the physics of the poop penguins, “these bombings sometimes embarrass caretakers in breeding environments like an aquarium,” the authors wrote. Therefore, “It is practically important to know to what extent your feces[[[[sic]arrive from the origin. Such information would save the guardians from the crisis. It would also be useful for a newcomer guide for caregivers to avoid such an incident. “
DOI: Polar Biology, 2003. 10.1007 / s00300-003-0563-3 (About DOIs).
