The naked mole-rat (Heterocephalus glaber), also known as the sand puppy,[6] is a burrowing rodent native to the Horn of Africa and parts of Kenya, notably in Somali regions.

[7] The naked mole-rat exhibits a highly unusual set of physiological and behavioral traits that allow it to thrive in a harsh underground environment; most notably its being the only mammalian thermoconformer with an almost entirely ectothermic (cold-blooded) form of body temperature regulation,[8] as well as exhibiting eusociality, a complex social structure including a reproductive division of labor, separation of reproductive and non-reproductive castes, and cooperative care of young.

[16] The naked mole-rat survives for at least 5 hours in air that contains only 5% oxygen; it does not show any significant signs of distress and continues normal activity.

For example, cold naked mole-rats huddle together or seek shallow parts of the burrows that are warmed by the sun.

[21] Naked mole-rats' substance P deficiency has also been tied to their lack of the histamine-induced itching and scratching behavior typical of rodents.

[24] In 2013, scientists reported that the reason naked mole-rats do not get cancer can be attributed to an "extremely high-molecular-mass hyaluronan" (HMW-HA) (a natural sugary substance), which is over "five times larger" than that in cancer-prone humans and cancer-susceptible laboratory animals.

[28] A few months later, the same University of Rochester research team announced that naked mole-rats have ribosomes that produce extremely error-free proteins.

[23][32][33] However, both animals were captive-born at zoos, and hence lived in an environment with 21% atmospheric oxygen compared to their natural 2–9%, which may have promoted tumorigenesis.

[40] Naked mole-rats are highly resistant to cancer[41]) and maintain healthy vascular function longer in their lifespan than shorter-living rats.

[43] The mechanisms underlying naked mole-rat longevity are debated, but are thought to be related to their ability to substantially reduce their metabolism in response to adverse conditions, and so prevent aging-induced damage from oxidative stress.

[7] Further transcriptome sequencing revealed that genes related to mitochondria and oxidation reduction are expressed more than they are in mice, which may contribute to their longevity.

In addition, several DNA repair pathways in humans and naked mole-rats were up-regulated compared with mice.

It is believed that this trait does not occur due to pre-existing morphological differences but to the actual attainment of the dominant female position.

[57] The naked mole-rat is native to the drier parts of the tropical grasslands of East Africa, predominantly southern Ethiopia, Kenya, and Somalia.

[58] Once established, the new queen's body expands the space between the vertebrae in her backbone to become longer and ready to bear pups.

The queen nurses them for the first month, after which the other members of the colony feed them fecal pap until they are old enough to eat solid food.

Naked mole-rats break this "one-half rule" – field caught and lab born litters averaged 11 to 12 pups, and numbers of mammae on wild and captive females were similarly 11 to 12.

Breeding female naked mole-rats can bear and successfully rear litters that are far more numerous than their mammae because young take turns nursing from the same mammary and breeding females and pups are fed and protected by colony mates, enabling queens to concentrate their reproductive efforts on gestation and lactation.

Smaller workers perform colony maintenance tasks such as foraging, nest building, and pup care.

[72] Dispersers are morphologically, physiologically and behaviorally distinct from colony members and actively seek to leave their burrow when an escape opportunity presents itself.

[72] Hence, disperser morphs are well-prepared to promote the establishment of new, initially outbred colonies, before cycles of inbreeding resume.

Invaders may kidnap small pups and incorporate them into their own colony's workforce, an intriguing convergence with the behavior of slave-making ants.

Evolutionarily, outbreeding may be preferred because it reduces the likelihood of expressing deleterious recessive alleles,[76] whereas inbreeding results in closer genetic relationships among naked mole-rat families, favoring self-sacrificial and nepotistic behaviors.

[58] Symbiotic bacteria in the mole-rats' intestines ferment the fibres, allowing otherwise indigestible cellulose to be turned into volatile fatty acids.

[78] Naked mole rats are primarily preyed upon by snakes—especially the Rufous beaked snake and Kenyan sand boa—as well as honey badgers and various raptors.

They are widespread, numerous and, being subterranean, essentially unnoticeable in the drier regions of East Africa (except for their small "volcanoes" of ejected earth).

[80] A naked mole-rat living at the Lincoln Children's Zoo was the first animal to be photographed for the National Geographic project, The Photo Ark, which has the goal of photographing all species living in zoos and wildlife sanctuaries around the globe in order to inspire action to save wildlife.