The naked mole rat , ( Heterocephalus glaber ), a burrowing member of the rodent family Bathyergidae , is named for its pale pink wrinkled skin and hairless body. Their broad heads have strong muscular jaws that support four incisors used for digging. They are famous for their longevity, low cancer rates, and colonial habits. Contrary to their name, naked mole rats have about 100 fine hairs on their skin that function like whiskers to help them sense their surroundings.

Naked mole rats can be found underground in grassy and semi-arid regions of East Africa, including Ethiopia, Kenya, Somalia and Djibouti. They live in underground burrows formed by an extensive network of tunnels that can be up to 2 meters (6.5 feet) deep and 4 kilometers (2.5 miles) long. They create tunnels about 4 centimeters (1.5 inches) in diameter by gnawing away dirt with their large teeth and sweeping it onto the surface in assembly-line fashion. The tunnels connecting the chambers are used for nesting, care, food storage, and other functions.

Natural history

Naked mole rats are typically 7.5 cm (3 inches) long and weigh about 28–42 grams (1–1.5 ounces), although their size can be larger depending on their role in the colony. Their bodies have developed several adaptations that allow them to live in underground habitats. They possess small eyes that make them almost blind. They have no external ear, and the inner ear lacks the structure that allows for cochlear amplification (a process that strengthens sound before it reaches the brain), contributing to hearing degeneration.

Naked mole rats rely on other senses, especially touch and smell, to navigate tunnels. The fine hairs on their bodies function as whiskers to sense vibrations and air currents in the cave, and their short legs allow them to easily move through the tunnels. A quarter of the naked mole rat’s muscle mass is in its jaw, while nearly a third of its somatosensory cortex, the area associated with touch, is devoted to its teeth.

Naked mole rats are herbivores and they eat parts of plants that grow below the surface, such as roots and tubers. If a large tuber is found, a naked mole rat can eat the inside and leave the outside intact, causing it to grow again and become a stable food source. They do not dig for water to drink because their diet provides enough moisture. Because digging for food is an energy-intensive process, naked mole rats practice fecal feeding: they re-eat their own feces to maximize the amount of nutrients absorbed from food.

Naked mole rats are one of the only truly social mammals – meaning they live in large groups defined by a hierarchical social structure, in which nearly all individuals cooperate to help a small number of individuals reproduce. The colonies are led by a female naked mole rat called the queen, who is the only female to reproduce. Queen termites mate with a small number of males and reproduce up to four or five times per year. Although the average size of a litter is about 12, this number is quite variable and can reach up to about 30 — one of the largest litter sizes of any mammal.

The other naked mole rats in the colony function as workers or soldiers. Worker ants are about 7.5 cm long and weigh 35 grams (1.25 ounces); they dig tunnels, collect food, and care for puppies. In contrast, soldiers use their relatively larger size, weighing about 55 grams (2 ounces), to protect the queen and her brood from snakes and other predators. The naked mole rat’s social nature is also helpful in temperature regulation; Unlike many other mammals, naked mole rats cannot maintain a steady body temperature and sometimes huddle together into large masses to conserve body heat.

Naked mole rats can live a long time, with an estimated lifespan of 10–30 years, much longer than other small rodents. Studies on naked mole rats have revealed that they defy Gompertz’s law, a mathematical equation developed by British mathematician Benjamin Gompertz that shows the risk of death increases exponentially with age.

While this risk of death doubles every eight years after age 30 in humans, the naked mole rat’s likelihood of dying appears to remain constant throughout its life. ( See also aging.) The International Union for Conservation of Nature and Natural Resources has classified Heterocephalus glaber as a species of least concern.

Anti-cancer

Research has revealed that the origin of these extended lifespans may be the tumor-free naked mole rat, the formation of malignant tumors. Although some cases of cancer have been reported in naked mole rats, their incidence of cancer is significantly lower than that of similarly sized animals as well as humans.

The key to their cancer-fighting abilities may come from the sugar molecule hyaluronan, which helps keep cells from clumping together to form tumors. Hyaluronan molecules are present in all animals, but they are extremely large in naked mole rats (about five times larger than molecules found in mice and humans), and the super molecules This large animal is not broken down by enzymes as quickly as in other animals.