Naked Mole-Rats Observed Surviving Long Periods Without Oxygen: How Do They Do It?

Naked mole-rats are among the strangest creatures in the animal kingdom. But they may have just gotten even stranger, thanks to their ability to last long without oxygen.

According to NPR, the African naked mole-rat has its fair share of unusual characteristics, including their hairless bodies, ground-dwelling tendencies, and the fact that they are one of the few cold-blooded mammals. The rodents are also renowned for being resistant to cancer, per previous studies. But a new study published in the journal Science suggests that they can survive oxygen deprivation for an extended period of time, further proving how differently their bodies function as compared to their fellow mammals. This was something study author Thomas Park and his fellow researchers had long been aware of.

“They have evolved under such a different environment that it’s like studying an animal from another planet,” said University of Illinois at Chicago neuroscientist Park in a statement.

This isn’t the first time naked mole-rats have been cited for their unusual characteristics. In 2011, the Inquisitr wrote about how these rodents live for about 25 years, a far longer lifespan than that of the average mouse. But what really interested scientists at that time was their ability to avoid cancer, even when scientists would try to create tumors in them.

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Two years later, researchers identified an agent within naked mole-rats that helps them avoid cancer – a “complex sugar” that prevents cells from bunching together and forming tumors in their bodies. While Science Magazine wrote that it wasn’t sure whether the agent could work with humans, cancer specialists acknowledged the research on the rodents as important in helping us understand the “regulatory role of the extracellular matrix” in cancer.

With all those interesting characteristics, there’s no doubt that naked mole-rats are fascinating members of the animal kingdom. But the new study didn’t have anything to do with the aforementioned cancer-related studies, but rather the rats’ uncanny survival skills in harsh living conditions.

NPR wrote how Park and his team were hoping to learn something new about naked mole-rats based on what they had already known about the animals. The creatures don’t generate their own heat in their underground habitats, but rather move to another tunnel, depending on the temperature; this allows them to expend less energy to survive. Their “sticky hemoglobin” also helps them in drawing oxygen from the extremely thin air in their tunnels, allowing them to survive for long periods despite the low oxygen and high carbon dioxide content of that air.

“We were thinking, ‘Gee, if you put all these things to bear on the problem of surviving in low oxygen, just how far can you go?'” Park told NPR. “And the naked mole-rats surprised everybody, I think.”

The naked mole-rats were placed in a chamber with just five percent oxygen content, a dangerously low percentage that could kill mice in less than a quarter of an hour. Five minutes later, the rats were still in good shape while inside the chamber, and as Park related, they were still fine after about an hour inside. Amazingly, they were slower and more sluggish, but still “chugging along” five hours later, leading Park to quip that the rodents had “more stamina than the researchers.”

Upping the ante on their experiments, Park’s team then placed the naked mole-rats in a chamber with zero oxygen content, which could kill a mouse in 45 seconds. According to NPR, the four rats in this second phase had “passed out” after half a minute, but weren’t dead – their hearts were still beating, and 18 minutes after being placed in the chamber, they awoke and were back to normal once they were breathing normal air again. The other three mole-rats who were deprived of oxygen for 30 minutes had died.

What makes naked mole-rats last so long without oxygen? Park says that it has something to do with a spike in fructose levels, which kicks in after about 10 minutes of oxygen deprivation. Apparently, the mole-rats switch from glucose to fructose when creating energy, as glucose needs oxygen for this process, whereas fructose doesn’t.

“We weren’t looking for it, but bang, fructose goes way up in the blood and then it goes way up in the organs and it gets used by heart and brain.”

University of Nebraska evolutionary physiologist Jay Storz, who was not involved in the study, told NPR that he was pleasantly surprised by the findings, as it suggests the ability of naked mole-rats to switch metabolic fuels is unique for vertebrates. He also believes that there may be other animals with such a peculiar ability, but that may require further studies when it comes to applying the findings to medical research.

[Featured Image by Joerg Sarbach/AP Images]