The Naked Mole Rat (Heterocephalus glaber), also known as the Sand Puppy, or desert mole rat, is a very unusual burrowing rodent native to parts of East Africa. They are the only species currently classified in genus Heterocephalus.
Typical individuals are 8–10 cm long and weigh 30–35 g. Queens are larger and may weigh over 50 g, the largest reaching 80 g. They are well-adapted for their underground existence. Their eyes are just narrow slits, and consequently their eyesight is poor. However, they are highly adapted to moving underground, and can move backwards as fast as they move forwards. Their large, protuding teeth are used to dig. They have little hair (hence the common name) and wrinkled pink or yellowish skin.
Clusters of 20 or 30 animals live together in complex systems of burrows in arid East African deserts. They have a complex social structure in which only one female (the queen) and one or two males reproduces. A behaviour called reproductive suppression is believed to be the reason why the other females do not reproduce, meaning the sterility in the working females is only temporary, and not genetic. Queens live from 13 to 18 years, and are extremely hostile to other females behaving like queens, or producing hormones for becoming queens. When the queen dies, another female takes her place, sometimes after a violent struggle with her competitors.
This eusocial organisation social structure is similar to that found in ants, termites, and some bees and wasps, is believed to be unique among mammals. The naked mole rat is also unique among mammals as it is cold-blooded; it cannot regulate its body temperature at all and requires an environment with a specific constant temperature in order to survive.
The skin of naked mole rats lacks a key neurotransmitter called Substance P that is responsible in mammals for sending pain signals to the central nervous system. Therefore, when naked mole rats are cut, scraped or burned, they feel no pain. When injected with Substance P, however, the pain signalling works as it does in other mammals.
In popular culture
A naked mole rat named Rufus is featured in the Disney cartoon Kim Possible.
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