# Naked Mole-Rat — Facts, Threats & Conservation

*Heterocephalus glaber (Rüppell, 1842) — family Heterocephalidae*

> The naked mole-rat (Heterocephalus glaber) is a eusocial East African rodent that lives in insect-like colonies with a breeding queen, tolerates extreme hypoxia and carbon dioxide, shows negligible ageing, resists cancer, and lacks normal acid pain sensation.

**IUCN status:** Least Concern — eusocial mammal with exceptional pain and cancer resistance  ·  **WARN range:** East Africa — Kenya, Somalia and Ethiopia, Semi-arid savanna and grassland

## Quick facts
| Fact | Value |
| --- | --- |
| Length | 8–10 cm body |
| Weight | 30–80 g |
| Social system | Eusocial — queen, breeders and sterile workers |
| Lifespan | 30+ years in captivity |
| Cancer | Extremely resistant — hyaluronan mechanism |
| Pain | No acid or capsaicin pain sensation |
| Habitat | Underground colonies in East African savanna |

## Scientific classification
- **Kingdom:** Animalia
- **Phylum:** Chordata
- **Class:** Mammalia
- **Order:** Rodentia
- **Family:** Heterocephalidae
- **Genus:** Heterocephalus
- **Species:** Heterocephalus glaber

## Conservation status
- **Status:** Least Concern
- **Population:** Unknown; considered common in suitable habitat
- **Trend:** Stable
- **Assessed:** 2016
- **CITES:** Not listed
- Locally affected by agricultural expansion and tuber harvesting, but the species remains common across its East African range.

## Key facts: Naked Mole-Rat
- Naked mole-rats are eusocial mammals — colonies have a breeding queen, a few males and many sterile workers, like an ant nest.
- They are essentially cold-blooded at rest, regulating temperature through behaviour rather than internal metabolism.
- They tolerate extreme hypoxia and high carbon dioxide in sealed underground burrows.
- They show negligible senescence and resist cancer through a unique cell-death mechanism involving hyaluronan.
- They cannot feel pain from acid or capsaicin, which may help them tolerate CO₂ in crowded tunnels.
- Lifespans exceed thirty years in captivity — extraordinary for a rodent of this size.
- Least Concern, but habitat disturbance and agricultural expansion affect local colonies.

## A mammal that lives like an ant
Naked mole-rat colonies contain a single breeding queen, one to three breeding males, and dozens to hundreds of sterile workers of both sexes. The queen is the only female that reproduces; she suppresses ovulation in other females through social dominance, physical contact and pheromonal cues delivered in the colony's shared toilet chamber.

Workers dig tunnels, forage for tubers, defend the colony and care for pups — without ever breeding themselves. This reproductive division of labour is eusociality, a social system previously known only in insects. Naked mole-rats are the most eusocial mammal, though Damaraland mole-rats show a similar system. Colonies can contain over 300 individuals in tunnel systems that extend for kilometres beneath East African savanna.

The tunnels are dug through hard, compacted soil using enormous incisors — a quarter of the animal's muscle mass is devoted to jaw muscles. Naked mole-rats can dig backwards as easily as forwards, shovelling excavated soil above ground with their heads. The colony's tunnel system is a permanent, expanding structure that may be occupied for many years, with new tunnels added as the colony grows and old sections abandoned as food in the area is exhausted. A single large tuber can sustain a colony for months.

## Cold-blooded, hypoxia-proof and long-lived
Naked mole-rats do not thermoregulate like normal mammals. At rest, their body temperature tracks the ambient temperature of the burrow — they are effectively poikilothermic, behaving more like a reptile than a rodent. They move to warmer or cooler tunnel sections to adjust, and huddle together when the burrow temperature drops. A colony huddled in a deep tunnel can maintain a workable temperature even when surface air falls sharply overnight in the savanna.

Their burrows are sealed environments where oxygen runs low and carbon dioxide accumulates. Naked mole-rats tolerate conditions that would kill most mammals: they can survive for minutes with almost no oxygen by switching to fructose-based metabolism, a pathway normally used by plants. Their lifespan exceeds thirty years in captivity — roughly ten times what a mouse of similar size would achieve — and they show negligible senescence, maintaining health, fertility and activity deep into old age.

The combination of hypoxia tolerance, negligible ageing and cancer resistance makes naked mole-rats the subject of intense biomedical research. Each trait addresses a major medical question — stroke treatment, ageing biology, oncology — and the fact that all three occur in one small rodent is what makes the species scientifically extraordinary rather than merely unusual.

## Cancer resistance and pain that is not there
Naked mole-rats almost never develop cancer. The mechanism involves high-molecular-weight hyaluronan, a substance in the extracellular matrix that triggers early contact inhibition — cells stop dividing when they touch neighbours, preventing the uncontrolled growth that becomes a tumour. When researchers suppressed hyaluronan production, naked mole-rat cells became cancer-prone, confirming the link.

They also lack normal acid pain sensation. Naked mole-rat nociceptors do not respond to acid or capsaicin — the compound that makes chilli peppers hot. This may be an adaptation to crowded burrows where carbon dioxide dissolves into tissue acid, which would cause constant pain in a normal mammal. The absence of acid pain is not a deficit but a feature of life in sealed tunnels where CO₂ levels can reach levels that would distress most animals.

These traits are not independent. The same hyaluronan that prevents cancer also contributes to skin elasticity and wound healing in the tight tunnels. The metabolic adaptations for hypoxia tolerance may interact with the ageing mechanisms that produce negligible senescence. Naked mole-rat biology is a package, not a collection of separate tricks — which is why the species has become one of the most intensively studied rodents in biomedical research worldwide.

## Why scientists study them obsessively
Naked mole-rats are a biomedical research model precisely because they break mammalian rules. Their cancer resistance, extreme longevity, hypoxia tolerance and pain insensitivity each address major medical questions. Understanding how their hyaluronan prevents tumour formation may inform human cancer therapy. Their fructose metabolism under hypoxia could inform stroke and heart attack treatment. Their negligible senescence challenges fundamental assumptions about mammalian ageing.

In the wild, they are Least Concern — colonies are common in suitable East African savanna across Kenya, Somalia and Ethiopia. Local threats include agricultural expansion, soil disturbance from ploughing and tuber harvesting that removes their primary food source. When farmers dig up the large underground tubers that naked mole-rats depend on, entire colony tunnel systems can lose their food base.

Captive colonies in research institutions worldwide maintain breeding populations for study, and the species breeds reliably in captivity — unlike many wild mammals that fail to reproduce under laboratory conditions. The naked mole-rat's combination of biological extremity and captive tractability makes it an ideal research subject. What is learned from them about ageing, cancer and hypoxia tolerance has direct relevance to human medicine — which is why a Least Concern rodent of East African savanna receives more laboratory attention than many Endangered mammals.

## What WARN does
WARN publishes free, sourced species education for animals whose biology challenges assumptions. The naked mole-rat is Least Concern and scientifically extraordinary — a combination that makes it worth covering because understanding unusual species broadens how people think about mammals altogether.

If this guide helps you understand wildlife and the pressures it faces, a gift to WARN supports habitat protection and free public education in our partner countries.

## Frequently asked questions: Naked Mole-Rat
### Are naked mole-rats really naked?
Mostly. They have almost no hair — a few sensory bristles on the body and hairs between the toes. Their pink, wrinkled skin is thin enough to see blood vessels through, which is why they look 'naked'.

### Are naked mole-rats eusocial?
Yes — the most eusocial mammal known. Colonies have a single breeding queen, one to three breeding males, and many sterile workers that dig, forage and defend without reproducing, similar to an ant or termite colony.

### Why do naked mole-rats live so long?
They show negligible senescence — barely ageing in the normal mammalian sense — and resist cancer through a unique mechanism involving high-molecular-weight hyaluronan. Captive lifespans exceed thirty years, roughly ten times what a similar-sized mouse would achieve.

### Can naked mole-rats feel pain?
They feel some pain but not acid pain or capsaicin pain. Their nociceptors do not respond to acid, which may help them tolerate the carbon dioxide that dissolves into tissue acid in their sealed, crowded burrows.

### Where do naked mole-rats live?
In underground colonies in the semi-arid savanna and grassland of East Africa — Kenya, Somalia and Ethiopia. They dig extensive tunnel systems and feed on large underground tubers.

### What do naked mole-rat / sand puppies eat?
The naked mole-rat (Heterocephalus glaber) is a eusocial East African rodent that lives in insect-like colonies with a breeding queen, tolerates extreme hypoxia and carbon dioxide, shows negligible ageing, resists cancer, and lacks normal acid pain sensation. The guide's ecology sections give the prey or forage detail behind that summary.

### Are naked mole-rat / sand puppies dangerous?
Naked Mole-Rat / Sand Puppies are not generally dangerous to people. The naked mole-rat (Heterocephalus glaber) is a eusocial East African rodent that lives in insect-like colonies with a breeding queen, tolerates extreme hypoxia and carbon dioxide, shows negligible ageing, resists cancer, and lacks normal acid pain sensation. Give wild individuals space and do not corner or handle them.

### How long do naked mole-rat / sand puppies live?
Naked Mole-Rat / Sand Puppies typically live 30+ years in captivity. The naked mole-rat (Heterocephalus glaber) is a eusocial East African rodent that lives in insect-like colonies with a breeding queen, tolerates extreme hypoxia and carbon dioxide, shows negligible ageing, resists cancer, and lacks normal acid pain sensation. Wild and captive figures can differ; use the sources listed on the guide for the underlying studies.

### How big is a naked mole-rat / sand puppy?
A Naked Mole-Rat / Sand Puppy is about 8–10 cm body. The naked mole-rat (Heterocephalus glaber) is a eusocial East African rodent that lives in insect-like colonies with a breeding queen, tolerates extreme hypoxia and carbon dioxide, shows negligible ageing, resists cancer, and lacks normal acid pain sensation.

## Sources
- [IUCN Red List — Heterocephalus glaber](https://www.iucnredlist.org/species/9987/115103465)
- [Smithsonian National Zoo — Naked Mole-Rat](https://nationalzoo.si.edu/animals/naked-mole-rat)

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Full guide: https://worldanimalrescuenetwork.org/wildlife-guides/naked-mole-rat