Body temperature, thermoregulatory behaviour and pelt characteristics of three colour morphs of springbok (Antidorcas marsupialis).
Using intra-abdominal miniature data loggers, we measured core body temperature in female springbok (Antidorcas marsupialis) of three colour morphs (black, normal and white), free-living in the Karoo, South Africa, for one year. During winter, white springbok displayed lower daily minimum body temperatures (37.4+/-0.5 degrees C), than both black (38.1+/-0.3 degrees C) and normal (38.0+/-0.6 degrees C) springbok. During spring, black springbok displayed higher daily maximum body temperatures (40.7+/-0.1 degrees C) than both white (40.2+/-0.2 degrees C) and normal (40.2+/-0.2 degrees C) springbok. These high maximum body temperatures were associated with larger daily amplitudes of nychthemeral rhythm of body temperature (2.0+/-0.2 degrees C), than that of white (1.6+/-0.1 degrees C) and normal (1.7+/-0.2 degrees C) springbok. Biophysical properties of sample springbok pelts were consistent with these patterns, as the black springbok pelt showed lower reflectance in the visible spectral range, and higher heat load from simulated solar radiation, than did the pelts of the other two springbok. Black springbok had lower diurnal activity in winter, consistent with them having to forage less because their metabolic cost of homeothermy was lower, but were disadvantaged in hot periods. White springbok, by contrast, were more protected from solar heat load, but potentially less able to meet the energy cost of homeothermy in winter. Thus energy considerations may underlie the rarity of the springbok colour morphs.
Hetem
Robyn S
RS
Brain Function Research Group, School of Physiology, University of the Witwatersrand, Johannesburg, South Africa. robyn.hetem@wits.ac.za
de Witt
Brenda A
BA
Fick
Linda G
LG
Fuller
Andrea
A
Kerley
Graham I H
GI
Meyer
Leith C R
LC
Mitchell
Duncan
D
Maloney
Shane K
SK
D000818:Animals; D000866:Antelopes; D001522:Behavior, Animal / Q000502:physiology*; D001833:Body Temperature Regulation / Q000502:physiology*; D002980:Climate; D005260:Female; D015203:Reproducibility of Results; D012879:Skin Physiological Phenomena; D012880:Skin Pigmentation; D013019:South Africa; D013997:Time Factors