Abstract:
The subterranean niche is a specialized environment that presents its inhabitants with a
unique set of microclimatic conditions. African mole-rats are strictly subterranean and exhibit
a continuum of sociality ranging from solitary to highly social. Colonies of the Damaraland
mole-rat comprise of a dominant breeding or reproductive female and one or two male
consorts and a number of subordinate and non-reproductive individuals of both sexes. In this
study we investigated the locomotor activity patterns of reproductive and non-reproductive
female Damaraland mole-rats with the intention to investigate daily timing of activity and
activity levels with changes in ambient temperature, and also whether activity would differ
between the reproductive castes at different ambient temperatures. The Damaraland mole-rats displayed predominantly nocturnal activity at all three
temperatures, and the levels of activity were different for all three temperatures tested. Molerats
exhibited the lowest levels of activity at 30ºC, they are most active at 25ºC while they
display intermediate levels of activity at 20ºC. Despite exhibiting the majority of their
activity during the night, non-reproductive females display significantly more day time
activity compared to the reproductive females at all three temperatures. Nocturnal activity is
comparable between reproductive and non-reproductive animals at 20 ºC and 25 ºC, but not
at 30 ºC.
Daily locomotor activity rhythms of the Damaraland mole-rats appear to be relatively flexible
and respond to comparatively small changes in ambient temperatures. Differences in daily
activity between reproductive and non-reproductive animals may emphasize the existence of
physiological and morphological castes in the Damaraland mole-rat.
