Abstract:
The relatively warm and very humid environment of burrows presents a challenge for
thermoregulation of its mammalian inhabitants. It was found that African mole-rats dissipate
body heat mainly through their venter, and social mole-rats dissipate more body heat compared to
solitary species at lower temperatures. In addition, the pattern of the ventral surface temperature
was suggested to be homogeneous in social mole-rats compared to a heterogeneous pattern in
solitary mole-rats. To investigate this for subterranean rodents generally, we measured the surface
temperatures of seven species with diferent degrees of sociality, phylogeny, and climate using
infrared thermography. In all species, heat dissipation occurred mainly through the venter and the
feet. Whereas the feet dissipated body heat at higher ambient temperatures and conserved it at
lower ambient temperatures, the ventral surface temperature was relatively high in all temperatures
indicating that heat dissipation to the environment through this body region is regulated mainly by
behavioural means. Solitary species dissipated less heat through their dorsum than social species,
and a tendency for this pattern was observed for the venter. The pattern of heterogeneity of surface
temperature through the venter was not related to sociality of the various species. Our results
demonstrate a general pattern of body heat exchange through the three studied body regions in
subterranean rodents. Besides, isolated individuals of social species are less able to defend themselves
against low ambient temperatures, which may handicap them if staying alone for a longer period,
such as during and after dispersal events.
