Study: Mammals can ‘breathe’ through their anus, humans possibly too

Mammals can take in oxygen through their anus, Japanese scientists have discovered. They were intrigued by how certain marine animals ‘breathe’ through their intestines in emergencies and decided to investigate how this works in mammals. Experiments showed that mice, rats, and pigs could get oxygen into their blood through their anus. According to the study published Friday in the journal Med, that may also be the case in humans.

Humans and many animals receive oxygen through their lungs or gills, but some fish and spider species have an emergency backup to survive, namely their anus. The researchers looked at whether something similar was possible in mice, rats, and pigs by depriving them of oxygen and then administering it through the anus, in gaseous form, and an oxygen-rich liquid through an enema.

To stimulate oxygen uptake, they rubbed the area around the animals’ anus. Since such treatment would meet with resistance in humans, they also tried it with a special liquid that has already been labeled as safe. With both methods, the test animals were found to take in more oxygen, after which their behavior normalized. The little liquid absorbed with the oxygen did not cause any damage. Patients with respiratory distress can be helped in this way, according to one of the researchers.

The Japanese team hopes to test the effectiveness of the technique in humans.