Socializing with Non-Naked Mole Rats; January 1995; Scientific American Magazine; by Holloway; 1 Page(s)
Big and hairy, the Damaraland mole rat is not as renowned as its hairless cousin. Nevertheless, this species has proved just as intriguing as the naked mole rat of zoo and cartoon fame. Both forms of mole rat are eusocial--that is, they live in groups in which only a queen and several males reproduce, whereas the rest of the colony cooperates to care for the young. This behavior--like that of termites and ants--is found in very few mammals, and it has remained a puzzle of natural selection.
By comparing Damaraland and naked mole rats, Jennifer U. M. Jarvis and Nigel C. Bennett of the University of Cape Town and others have begun to determine the characteristics that appear central to the evolution of eusociality--and hair is clearly not one of them. "The Damaraland is important because it does not have many of the characteristics of the naked mole rat," notes Paul W. Sherman of Cornell University. So it "tells us something that we did not know." The degree of genetic relatedness between members of a colony, for instance, does not appear as crucial to eusociality as some had believed. In the case of naked mole rats, siblings raise one another because the survival of a sister or brother is virtual cloning. A Damaraland colony, however, appears much more genetically diverse. Once a queen dies, these mole rats wait to reproduce until another female is introduced from somewhere else--at least in the laboratory.