Jum. Jarvis et Nc. Bennett, EUSOCIALITY HAS EVOLVED INDEPENDENTLY IN 2 GENERA OF BATHYERGID MOLE-RATS - BUT OCCURS IN NO OTHER SUBTERRANEAN MAMMAL, Behavioral ecology and sociobiology, 33(4), 1993, pp. 253-260
Extensive field and laboratory studies show that Damaraland mole-rats,
like naked mole-rats, have an extreme form of vertebrate sociality. C
olonies usually contain 2 reproductives and up to 39 non-breeding sibl
ings, 90% of whom live a socially-induced lifetime of sterility; they
remain in the natal colony, forage for food, defend the colony and car
e for successive litters. Although there is heightened dispersal follo
wing good rainfall, the majority of adult non-reproductives remain in
their natal colony and failure to disperse is not directly attributabl
e to habitat saturation or unfavourable soil conditions. A major dispe
rsal event follows the death of a reproductive. Differences in colony
cohesion, ethology and the hormonal profiles of non-reproductive anima
ls suggests that eusociality evolved along different pathways in these
two phylogenetically divergent genera of the Bathyergidae.