Researchers Find Some Mammals Can Breathe Out of Their Butts and Hope Humans Can Too

Mammals can only breathe through their noses and mouths—or so we thought. New findings published in Med on Friday suggest that pigs, rats, and mice are actually capable of breathing through their intestines, via their anuses.

Now, you may be wondering: why would scientists be so interested in learning about butt-breathing? The answer is surprisingly relevant to our times. According to Live Science, the research brings us one step closer to finding an alternative to standard ventilators in medical settings.

While ventilators are often effective, the study notes that they sometimes come with additional complications, like lung injury. Perhaps even more importantly, the COVID-19 pandemic has highlighted the scarcity—and desperate need—for ventilators worldwide.

"The SARS-CoV-2 pandemic has overwhelmed the clinical need for ventilators and artificial lungs," reads the study, "resulting in a critical shortage of available devices and endangering patients' lives worldwide." This research into intestinal ventilation suggests "an alternative patients who are in critical need of respiratory support."

Notably, these mammals are not the only creatures found to have this unique ability: ocean animals like sea cucumbers are known to respirate through their intestines, says Live Science. Taking those animals as inspiration, scientists hoped that mammals might possess the same capabilities.

As Dr. Takanori Takebe, a head author of the study, told the news outlet, the researchers "were quite surprised" at their results.

The experiment put two groups of mice in a low-oxygen environment. One group was given intestinal ventilation, and one was not. The group that received oxygen via intestinal ventilation—in other words, had oxygen pumped up their behinds—survived far longer on average than those without it.

The practice was shown to be especially promising when the mice were given oxygenated perfluorodecalin (PFD), a liquid substance infused with oxygen rather than the gas itself. When tested on pigs, oxygenated PFD continued to show positive results.

"Both intra-rectal O2 gas and oxygenated liquid delivery were shown to provide vital rescue of experimental models of respiratory failure," reads the study, thus "improving survival, behavior, and systemic O2 level."

Now, further research is needed to see if the technique is safe for trial on humans. According to Live Science, Dr. Takebe hopes to start a clinical trial of the practice in human volunteers as soon as next year. However, several uncertainties still lie ahead.

For example, the condition of the animals tested in the experiments doesn't necessarily compare to that of humans undergoing true respiratory failure, which often comes with numerous other issues. Additionally, the treatment could potentially disturb the vagus nerve, which connects the brain and gut, causing blood pressure changes and fainting.

However, should the treatment be approved and deemed effective for humans, the practice could revolutionize intensive-care units worldwide.

Pigs in Germany
Piglets at a hog farm in Germany, April 2016. Carsten Koall/Getty Images