BiologyCoachOnlineBlog

Last week's ‪#‎MysteryCreature‬ was the Naked Mole-rat (Heterocephalus glaber).

The Naked Mole-rat, also known as the sand puppy, is a burrowing mammal native to parts of East Africa. It is the only species classified in the genus Heterocephalus. The naked mole-rat averages between about three- and four-inches (8-10 cm) in length. They may weigh up to just over an ounce (35-grams). The naked mole-rat is the first mammal discovered to exhibit eusociality (similar to that found in ants, termites, bees, and wasps. A naked mole-rat colony consists of a single female (the queen) and one to three breeding males. The remaining members of the colony are (sterile) workers. Worker members gather food, maintain tunnels, and protect the colony. Workers also care for the pups by keeping them from straying, grooming them, and keeping them warm. Naked mole-rats feed primarily on large tubers that they find through their mining operations. They eat the inside of the tuber while allowing the outside to regenerate. This practice provides the colony with a long-term source of food.

The naked mole-rat is quite well-adapted to life in its underground labyrinthe. Its lungs are very small and its blood has a very strong affinity for oxygen (thereby increasing the efficiency of oxygen uptake). It has a very low respiration and metabolic rate for an animal of its size as well. In fact, the naked mole-rat can reduce its metabolic rate by as much as 25-percent (in response to longer periods sans food).

Unlike a typical mammal (which is a thermoregulator), naked mole-rats are thermoconformers. That is, they adjust their body temperatures according to local ambient temperatures. In other words, as local ambient temperature decreases, the naked mole-rat's effective body temperature likewise decreases. As local ambient temperature rises, the animal's effective body temperature concurrently rises.

The skin of the naked mole-rat lacks the neurotransmitter (i.e. Substance-P) that is responsible for sending pain signals to the brain. As a result, naked mole-rats feel no pain (even when exposed to acid). [It has been posited that this is an adaptation to living in their poorly-ventilated, underground lairs (where high levels of carbon dioxide would cause acid to build up in their body tissues).]

Finally, the naked mole-rat can live up to 30-years (an extraordinarily long lifespan for a rodent of its size). Their unusual longevity is thought to be related to their ability to reduce their metabolism thereby preventing age-inducing damage from oxidative stress.