The Mammalian in Insect-like Dwellings
Naked mole rats, Heterocephalus glaber, are found in arid areas of Eastern Africa.
Living in Colonies
They inhabit in extensive burrow system underground in large colonies of up to three hundred animals. These rodents are the only known mammals with the establishment of a hierarchy similar to that of ants and bees—of a single queen and its workers.
The “queen” has a larger physique than the other females in the community and principal role is in reproducing and raising pups. She mates with up to three breeding males that also aid in rearing these pups. The non-breeding mole rats are workers whereby smaller ones participate in maintenance activities like nest building and foraging while larger ones engage in colony defense and attend to the queen and her young.
Transgressing the Hierarchy
Unlike insects, mole rats are not predestined to belong to a particular caste. They are able to move up the hierarchy as they age and grow in size.
Also, unlike workers in insect colonies that are sterile, non-breeding naked mole rats have their reproductivity suppressed. Biologists postulated this suppression to be due to the release of pheromones by the queen and the result of physical contact with the queen as she intentionally knocks into or shove these workers. When the queen dies, she becomes replaced by one of the non-breeding females that compete to become queen. The new queen physiologically elongate as she regain fertility.
Why they live as such
Richard Alexander, an evolutionary biologist, posits that naked mole rats can forgo mating and still sustain an entire colony for years as one queen can reproduce enough offspring in her lifetime to provide ample workers. The passing on of genes is thus better sustained with the other members tending to the young than producing their own.
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Jarvis, J. (1981). Eusociality in a mammal: Cooperative breeding in naked mole-rat colonies . Science, New Series, 212(4494), 571-573.
Morelle, R. (2010, May 5). Meet the ‘sabre-toothed sausage’. BBC News Science and Environment. Retrieved from http://www.bbc.co.uk/news/10088502 (accessed on 6 Apr 2013)
World’s Weirdest : Naked Mole Rats by National Geographic. NatGeoWild YouTube channel, 6 June 2012. Retreived from http://www.youtube.com/watch?v=A5DcOEzW1wA (accessed on 9 Apr 2013)