Naked mole rats' strangest trick? Thriving without oxygen

Admittedly, the naked mole rat may not be the most attractive animal on earth, but what they lack in looks, they make up for in quirky, fascinating traits. Counter to most mammals, they are hairless, live underground and are cold-blooded.

Mole rats are endlessly fascinating to health researchers for many reasons. They have few pain receptors and are resistant to cancer.

However, it was a recent study that really shook up researchers. It was found that naked mole rats are very adept at surviving low-oxygen situations. They can survive for a significant amount of time with absolutely no oxygen and indefinitely on very low oxygen levels.

Naked mole rats survived with no ill effects for a whopping 18 minutes on no oxygen. Humans, in contrast, suffer significant brain damage after only 3 minutes of oxygen deprivation. In air containing only 5 percent oxygen (a quarter of oxygen content of normal air) mole rats can survive indefinitely, whereas mice expire in less than 15 minutes.

Researchers were astonished at these results.

In testing behavior in low oxygen, the researchers -- who were expecting a somewhat short experiment -- were hungry and tired and ready to go home, whereas the mole rats were still going strong after five hours.

How can they possibly do this? For starters, being ground dwellers, mole rats are used to low-oxygen environments. They save energy (and thus oxygen) by regulating their heat by moving to warmer or cooler tunnels, versus generating their own heat. They also have "sticky hemoglobin" which allows them to "grab" more oxygen out of thin air.

But the big finding in this study was that in low-oxygen situations they are able to switch their energy source. They go from burning glucose, like all other mammals, to burning fructose, which does not require oxygen to convert to energy. This switch to an alternative fuel is significant.

Researchers are hoping that studying this phenomenon in naked mole rats could someday help develop a way to aid patients suffering from oxygen deprivation due to something like a heart attack or stroke.

The Pueblo Zoo is home to two groups of naked mole rats. The larger of the two consists of six adults and nine new babies. Guests often raise the alarm that the rats look dead, but this is all part of their ability to slow down and conserve energy and oxygen. For those not squeamish, one can gaze and wonder upon these fascinating creatures in the EcoCenter building.

Source: http://science.sciencemag.org/content/356/6335/307