What you didn't know about naked mole-rats

October 22, 2015 by Fariss Samarrai, University of Virginia
As it turns out, naked mole-rats have been misunderstood for decades. Credit: Meghan Murphy/Smithsonian’s National Zoo

The naked mole-rat is a particularly ugly or cute animal, depending on your definition. It is tubular in shape, like the tunnels it creates, hairless and wrinkled, for wiggling through those tunnels, and has long, chisel-like front teeth. It looks somewhat like a walrus in miniature. And these rodents can chew through concrete!

Do a Google search of the , or read through a number of biology textbooks, and you will find numerous references to this African mammal as being "inbred" and "eusocial," meaning – similar to some insects – it has a fertile "queen" at the head of the colony, helpers who tend to her and may mate with her, and female "workers" who are sterile, expending their energy building tunnels and finding food.

This social system is rare among animals, and almost unheard-of among mammals, so have long taken particular interest in the unusual eusocial mating system of the naked mole-rat and its essentially homogeneous genetics. Why would this rodent have evolved to socialize and mate so differently from other mammals? From a natural selection standpoint – where advantageous traits are passed down to succeeding generations – what is gained by limiting genetic diversity by limiting the breeding pool?

Evolutionary biologists have puzzled over and debated this for decades. For this reason, the naked mole-rat has been an interesting oddball study model.

Well, it turns out the long-held conventional wisdom about the naked mole-rat being inbred is wrong, according to a University of Virginia-led study published recently in the journal Molecular Ecology.

UVA biologist Colleen Ingram has discovered that a commonly studied rodent is not an inbreeder, as once thought. Credit: Dan Addison

UVA biologist Colleen Ingram and a team of researchers from several U.S. universities and the American Museum of Natural History conducted genetics studies of different mole-rat populations from Africa, and compared them to the genetics of a long-studied mole-rat population. They found that the populations of mole-rats studied for decades are "inbred" only because they originally came from a small, genetically isolated population of naked mole-rats from south of Kenya's Athi River. The researchers discovered that larger wild populations from north of that river and from the Tana River region are genetically variable, like other mammals – meaning they are not inbred, despite their unusual eusocial mating behavior.

"We now know, from looking at the big picture from a much larger geographic area than previously studied, that the naked mole-rat is not inbred at all," Ingram said. "What we thought we knew was based on early genetics studies of a small inbred sample from an otherwise genetically variable species. This shows that long-held assumptions, even from heavily studied model species, can and should always be questioned and further studied."

It also suggests, she said, that laboratory animals, isolated and repeatedly re-bred for studies, might over time represent behaviors and genetics that are different from the diverse wild populations from which they originally came.

The study also means that some biology websites and textbooks need updating.

Explore further: Naked mole-rats' anti-cancer gene is unique among mammals

Related Stories

Naked mole-rats' anti-cancer gene is unique among mammals

May 6, 2015

Naked mole rats are unusual in many ways as a result of adaptations to living underground, with extreme longevity and a lack of the normal signs of ageing. Their resistance to cancer has been linked to the production of a ...

Hope for healthy hearts revealed in naked mole rat studies

August 19, 2014

Cardiovascular disease is the greatest killer of humans the world over, presenting huge financial and quality-of-life issues. It is well known that the heart becomes less efficient with age in all mammals studied to date, ...

Bottom of the swimming league: Naked mole rat sperm

December 5, 2011

Naked mole rats (Heterocephalus glaber) live in a 'hive' society with one reproducing queen and between one and three reproducing males. The rest of the mole rats in the colony are workers either defending the burrow or finding ...

The naked mole-rat's secret to staying cancer free

July 31, 2013

A team of researchers from the University of Rochester (NY) and the University of Haifa discovered the naked mole rat's unique mechanism to staying cancer free- a super sugar called high-molecular-mass Hyaluronan (HMM-HA). ...

Naked mole rat may hold the secret to long life

July 2, 2012

Compared to the average three year life span of a common rat, the 10 to 30 year life of the naked mole rat, a subterranean rodent native to East Africa, is impressive. And compared to the human body, the body of this rodent ...

Recommended for you

Sculpting stable structures in pure liquids

February 21, 2019

Oscillating flow and light pulses can be used to create reconfigurable architecture in liquid crystals. Materials scientists can carefully engineer concerted microfluidic flows and localized optothermal fields to achieve ...

Researchers make coldest quantum gas of molecules

February 21, 2019

JILA researchers have made a long-lived, record-cold gas of molecules that follow the wave patterns of quantum mechanics instead of the strictly particle nature of ordinary classical physics. The creation of this gas boosts ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.