TY - JOUR
T1 - The importance of microhabitat in thermoregulation and thermal conductance in two namib rodents-a crevice dweller, Aethomys namaquensis, and a burrow dweller, Gerbillurus paeba
AU - Buffenstein, Rochelle
N1 - Funding Information:
Acknowledgements--I wish to acknowledge financial support through a CSIR bursary. I sincerely thank Professor J. U. M. Jarvis and Dr B. Leon for their criticism of this manuscript and Ms D. Gianakouros for her help with the figures. I would also like to thank Dr E. Joubert and the SWA Department of Nature Conservation for permission to work in the Namib Desert Park.
PY - 1984/10
Y1 - 1984/10
N2 - 1. 1.|Thermoregulatory measurements of two Nambi rodents; Gerbillurus paeba, a burrow dweller, and Aethomys namaquensis, a crevice dweller were compared. Both were similar to other small arid-adapted rodents in that basal metabolic rates were reduced, thermoneutral zones narrow and evaporative water losses low. Rates of conductance and thermal lability, however, at ambient temperatures (Ta) below thermoneutral zone, were significantly different (P ≤ 0.01). 2. 2.|The rock rat A. namaquensis, living in a microclimate characterized by a large diel range and low humidities, compensates for a reduced basal metabolic rate by having a low rate of conductance. In this way it maintains precise thermoregulatory control. G. paeba, on the other hand, living in a thermally-stable milieu, does not control body temperature precisely. This animal instead utilizes a high rate of conductance to remove metabolic heat produced within the body. This would be advantageous to an animal living in a plugged burrow where the high humidities encountered impede the rate of evaporative cooling. 3. 3.|The energetic responses of both species, above the thermoneutral zone, appear to reflect very closely the environmental conditions which occur in the microhabitat that they rest in during the day. G. paeba shows less tolerance to temperature fluctuations than A. namaquensis, but shows more marked increases in short-term cooling mechanisms at high Tas. 4. 4.|Despite the increased use of evaporative cooling through salivation and panting in addition to pulmocutaneous evaporation, exposure to Tas above 38°C is rapidly lethal to G. paeba.
AB - 1. 1.|Thermoregulatory measurements of two Nambi rodents; Gerbillurus paeba, a burrow dweller, and Aethomys namaquensis, a crevice dweller were compared. Both were similar to other small arid-adapted rodents in that basal metabolic rates were reduced, thermoneutral zones narrow and evaporative water losses low. Rates of conductance and thermal lability, however, at ambient temperatures (Ta) below thermoneutral zone, were significantly different (P ≤ 0.01). 2. 2.|The rock rat A. namaquensis, living in a microclimate characterized by a large diel range and low humidities, compensates for a reduced basal metabolic rate by having a low rate of conductance. In this way it maintains precise thermoregulatory control. G. paeba, on the other hand, living in a thermally-stable milieu, does not control body temperature precisely. This animal instead utilizes a high rate of conductance to remove metabolic heat produced within the body. This would be advantageous to an animal living in a plugged burrow where the high humidities encountered impede the rate of evaporative cooling. 3. 3.|The energetic responses of both species, above the thermoneutral zone, appear to reflect very closely the environmental conditions which occur in the microhabitat that they rest in during the day. G. paeba shows less tolerance to temperature fluctuations than A. namaquensis, but shows more marked increases in short-term cooling mechanisms at high Tas. 4. 4.|Despite the increased use of evaporative cooling through salivation and panting in addition to pulmocutaneous evaporation, exposure to Tas above 38°C is rapidly lethal to G. paeba.
KW - Aethomys namaquensis
KW - Gerbillurus paeba
KW - Namib
KW - Thermoregulation
KW - burrow dweller
KW - crevice dweller
KW - desert
KW - evaporative water loss
KW - metabolic rate
KW - thermal conductance
UR - http://www.scopus.com/inward/record.url?scp=0000868326&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0000868326&partnerID=8YFLogxK
U2 - 10.1016/0306-4565(84)90002-0
DO - 10.1016/0306-4565(84)90002-0
M3 - Article
AN - SCOPUS:0000868326
VL - 9
SP - 235
EP - 241
JO - Journal of Thermal Biology
JF - Journal of Thermal Biology
SN - 0306-4565
IS - 4
ER -