The naked mole-rat is an intriguing animal. This rodent defies all the laws of mammals—they’re hairless, almost blind, and cannot regulate their temperature. Living exclusively underground in arid regions of East Africa, they had to evolve some astounding adaptations.
Naked mole-rats are a lot more than meets the eye. In this species highlight, we’ll give an overview of the exciting life of this scientific marvel. You will get to know your new favorite animal and have some new interesting conversation starters.
|Common Name||Naked mole-rat|
|Other Names||Sand puppy, desert mole-rat, The Methuselah mouse|
|Social Organization||Eusocial, colony|
|Habitat||Underground in semi-arid land|
|Distribution||East Africa – Somalia, Kenya, Ethiopia|
|Lifespan||Up to 30 years|
|Weight||0.5-2.5 ounces (15g-70g)|
|Body length||2.7-4.3 inches (70–110 mm)|
|Tail length||1.18-1.96 inches (30–50mm)|
|Color||Pink with shades of purple, yellow, and brown|
|Skin Type||Nearly hairless skin|
Naked Mole Rat Pictures
The naked mole-rat is undoubtedly a sight to see. They rarely break the earth’s surface to see the light of day. Pictures like these and zoo collections are your best chance to see one.
5 Interesting Naked Mole-Rat Facts
1. They Are the Oldest Living Rodents
Rodents tend to have short lifespans when compared to larger mammals. Other similar-sized rodents have average lifespans of 3–7 years. The naked mole-rat defies the laws of aging and can live up to 30 years. The oldest recorded reached 28.
2. They Might Be Immune to Cancer
Thorough research shows that naked mole-rats have cells resistant to tumorous cancers.
Their high levels of hyaluronan are behind this. it is five times higher than other rodents. Efficient ribosome function in cells also produces more error-free proteins, making abnormalities rare.
There are two cases of tumors in naked mole-rats. Both occur in zoo populations where the oxygen levels were at 20% compared to 2–8% in their wild habitat.
3. They Are Resistant to Pain
Naked mole-rats lack neurotransmitters in their skin nerve cells. Studies show that they do not respond to the pain inflicted by capsaicin or acid. This is an adaptation for managing high carbon dioxide levels, which causes an acid build-up in body tissue.
4. Their Burrows Are Perfectly Designed
Each naked mole-rats colony has a burrow and tunnel system. Each chamber in their home has a different purpose. There is a designated spot to store food, a place to sleep, a “bathroom” for excretions, and a nursery for pups.
5. Their Teeth Can Move Independently
Naked mole-rat teeth are a distinctive feature used to dig through the substrate and eat rigid structures of plants. Each set of incisors can move independently from the other to facilitate this.
Scientists found the part of a naked mole-rat brain responsible for touch is enlarged. From this, one-third is connected to the teeth, proving how important their teeth are in interacting with the environment.
Naked Mole-Rat Classification and Evolution
Naked mole-rats are neither rats nor moles. Naked mole-rats are evolutionarily distinct from their closest relatives. They exist in a family of their own, relating to the other mole-rat species on a parvorder level. Other mole-rats are in the blesmol family, which has 21 described species.
The source of the naked mole rat’s unique evolution to an underground, eusocial mammal is still under research. Many other related species do not exhibit the same behaviors despite having similar habitats and diets.
These extraordinary animals have a range of incredible adaptations that help them thrive in their environment.
Naked Mole-Rat Evolutionary Adaptations
|Pain insensitivity||High carbon dioxide environment|
|Lips behind teeth||Keeping dirt out of the mouth while tunneling|
|Large incisors & strong jaws||Digging tunnels and consuming hard plant matter|
|Facial hair/whiskers||Sensory in dark environments|
|Hair between toes||Sweeping dirt while digging|
|Tunneling behavior||Protected from predators and elements|
|Low metabolism and respiration rate||Low oxygen environments|
|Efficient hemoglobin and underdeveloped lungs||Low oxygen environments|
|Wrinkly skin||Reduces friction to prevent injuries, ease of navigation in crowded spaces|
Naked Mole-Rat Appearance and Anatomy
Naked mole-rats are the smallest mole-rat species with an average weight of 1 ounce (30g). They have pink, folded skin, which makes them look hairless. They have short sensory hairs mostly around their face and feet. Two large pairs of teeth sit on the outside of their lips.
The average size of a naked mole-rat is 30 to 35g. The naked mole-rat Queen will be larger, up to 80g. They are 8 to 10cm from the nose to the tail.
Despite being named “naked,” these creatures have small amounts of hair over their whole body. Hair is most dense near the face and nose as it acts as a sensory organ.
Naked mole-rats have hair between their toes that acts as a “broom” to sweep away dirt efficiently while they dig.
Their skin is pink in color. Naked mole-rats have no internal fat layer under the skin for thermoregulation. Shades of purple, yellow, and brown can give a transparent look.
Eyes, Ears & Mouth
Contrary to common belief, naked mole-rats are not entirely blind. Their eyes are small and underdeveloped due to lack of use. The naked mole-rats brain lacks visual processing. Instead, it emphasizes tactile inputs.
Their ears are small holes surrounded by a slight bunching of skin on each side of the head.
The mouth has two large sets of incisors, with lips that can close behind them, allowing digging without the risk of ingesting dirt.
Naked mole-rats have relatively short legs. They allow the animals to move through tight tunnels. Despite their size, their legs can move them backwards just as fast as forwards.
Naked Mole-Rat Distribution and Habitat
Naked mole-rats live in underground tunnels and burrows in warm, dry regions of East Africa. They are found in Ethiopia, Kenya, and Somalia. The accurate distribution of this species is unknown due to their elusive lifestyle.
The described distribution of naked mole-rats is exclusively in the above three African countries. Researchers suggest that the actual distribution of these rodents may be unknown, as their underground presence may be going undetected in areas.
Their habitat is in semi-arid regions with high temperatures and low rainfall. They prefer compact soils, which grow favorable food and provide structure for tunnels and are found less in rocky or loose soil.
Naked Mole-Rat Social Structure
Naked mole-rats are one of only two species that display a eusocial structure. Colonies can have between 20–300 individuals with one Queen who mates with one to three males. The rest of the colony work cooperatively for survival.
Eusocial behavior is a rare social structure that goes against Darwin’s theory of evolution: that each animal wishes to reproduce. Eusocial animals give up reproduction to support a colony and raise the offspring of another.
This behavior is most common in animals such as termites, ants, and bees. Naked mole-rats and Darmaland mole-rats are the only two species of mammals that have evolved this behavior.
Naked mole-rats will live in colonies of 20–300, averaging at 75. There are three general roles in the colony:
The naked mole-rat Queen is the dominant female. She is larger than the others and is the only female to reach sexual maturity. Her excreted hormones and physical shoving stifle the hormones of other females, rendering them asexual.
If she dies, other females begin producing hormones until a dominant female emerges, becoming the next Queen.
The Queen is the only naked mole-rat to produce offspring with 1–3 unrelated mates. These males tend to be dominant due to their body size and physical fitness.
The majority of the colony members are workers. They work by creating tunnels to collect and store food. Workers will also bring food directly to the Queen and tend to her pups. The duties of each worker will depend on their size. As they grow, they will get more challenging tasks.
Some workers will function as soldiers who will defend the colony in the face of threats. They will band together to confront any approaching predators.
On rare occasions, pup litters contain “disperser morphs.” These individuals are born differently from the rest of the litter, both behaviorally and physically. They have extra fat supplies and higher levels of hormones.
They do not actively work with their colony. Instead, they travel outside their family unit to find other colonies to breed with, preventing inbreeding.
Naked Mole-Rat Behavior and Lifestyle
The underground habitat dictates naked mole-rat behavior. Due to the dark environment, they do not have a set circadian rhythm that dictates activity. Their inability to thermoregulate encourages them to be physically close to each other.
Many species rely on their inner circadian rhythm to dictate their physical and behavioral changes. This instinct responds to the day/night cycle and the changing daylight hours through the seasons.
Naked mole-rats live in constant darkness, and their habitat’s ambient temperature remains relatively constant. Their behavior is random. Rest and active tasks are sporadically done independently of each other.
The stable temperatures underground have evolved an inability to thermoregulate. Naked mole-rats sleep and operate closely to keep internal temperatures steady.
Naked Mole-Rat Diet
Naked mole-rats primarily eat the underground parts of plants, including roots and tubers. They consume their feces, and bones on rare occasions.
Underground plant storage, such as roots and tubers, is a naked mole-rat’s main diet. Various plants offer the full range of their nutritional and water requirements. Large tubers can provide a long-term food source by regenerating from the core.
They also eat their feces and other colony members to absorb originally undigested plant matter. The Queen’s feces also provide maternal hormones to stimulate workers to care for her pups.
Related: What Do Naked Mole-Rats Eat?
Naked Mole-Rat Predators and Threats
Naked mole-rats have few predators. They are mostly predated upon by snakes who can access their tunnels. They are also vulnerable to raptors if they breach the ground’s surface.
They do not share their habitat with many other animals. Populations are markedly less in areas with other burrowing species to compete with.
Mole-rats are most at risk of being predated by snakes, which can quickly move inside their tunnels. On occasion, raptors will prey on the odd mole-rat that digs to the surface.
Threats include unfamiliar colonies, which will incite aggression if encountered.
These tiny but mighty mammals face threats front-on. Large soldier mole-rats will pile on top of each other to block the tunnel, creating a barrier with their large teeth. Another mole-rat will return to the colony to warn them of the dangers so other resting soldiers can be on guard, particularly protecting the Queen.
Naked Mole-Rat Reproduction, Life Cycle, and Lifespan
Naked mole-rats have only one reproducing female per colony. She breeds continuously if the food supply is adequate. Litter size ranges from 3 to 12 but can be up to 28. Workers of the colony care for the offspring until they wean.
The Queen is the only female to reproduce within the colony. She will choose 1–3 strong and unrelated males to mate with. Her body alters to carry pups as her spine extends to create more internal space.
The Queen does little to care for her young. Caretakers carry them to her for feeding. These workers will also groom the baby naked mole-rats and assist them as they wean.
|Esterus period||less than 24 hours|
|Gestation||70 days (66–74 range)|
|Litter size||3–12 (can be up to 28)|
|Litters per year||In the wild: 1–5In captivity: every 80 days|
|Size of young||2 grams|
|Lactation period||3–5 weeks|
|Weaning period||3–8 weeks|
|Low ranking juvenile stage||up to two years|
|Sexual maturity (breeding individuals)||7–9 months|