Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2009 Dec 23;5(6):853-6.
doi: 10.1098/rsbl.2009.0450. Epub 2009 Jul 15.

Strategic (adaptive) hypothermia in bull dromedary camels during rut; could it increase reproductive success?

Gordon Grigg  1 , Lyn Beard, Birgit Dörges, Jürgen Heucke, Jocelyn Coventry, Alex Coppock, Simon Blomberg
Affiliations

Strategic (adaptive) hypothermia in bull dromedary camels during rut; could it increase reproductive success?

Gordon Grigg et al. Biol Lett. .

Abstract

In this study of body temperatures (T(b)) in free ranging dromedary camels, we found that bulls in rut start the days cooler. Daily minima during rut averaged 0.6 degrees C lower than at other times (95% CI 0.27-0.94 degrees C) and daily maxima averaged 0.45 degrees C higher (95% CI -0.01 to -0.91 degrees C), increasing the daily T(b) cycle. Knut Schmidt-Nielsen described a similar pattern in captive dromedaries deprived of water in hot conditions, which he interpreted as a strategy to conserve water. Our observations were made in winter and with water freely available. Dromedaries can apparently employ heterothermy for more than just water conservation. In the strenuous daily contests between rival bulls in rut, a lower T(b) early in the day should extend the time for which a contestant can challenge or defend before heat stress becomes a problem. Calculations show that lowering T(b) by even 0.6 degrees C extends that time by more than 30 min, and many daily minima during rut were lower than that. Because the eventual winner of contests gains or retains a herd of females, we speculate that cooler T(b) at the start of daily contests confers an advantage which translates directly into increased reproductive success.

PubMed Disclaimer

Figures

Figure 1.
Figure 1.
Daily maximum and minimum body temperatures from approximately 10 months of data from each of four male camels plotted against the time of year. Inset: Daily cycles in body temperature in one of the bulls during 2000; note the increased daily ranges after mid-April when the animal was in rut. Filled circle, max; open triangle, min.
Figure 2.
Figure 2.
Combined frequency histogram of daily maximum (open) and minimum (closed) body temperatures of four males during (a) rut and (b) non-rut sampling periods including and surrounding those identified in table 1 and for (c) four females during June and July (within male rut period); n = 127, 121, 124 (top to bottom).
See this image and copyright information in PMC

References

    1. Box G. E. P., Jenkins G. M., Reinsel G. C.1994Time series analysis. Forecasting and control, 3rd edn London, UK: Prentice-Hall
    1. Grigg G. C., Beard L. A.2001Application of radiotelemetry to studies of the physiological ecology of vertebrates. In Proc. of 15th International Conf. on Biotelemetry, Juneau, Alaska, 9–14 May 1999 (eds Eiler J. H., Alcorn D. J., Neuman M. R.), pp. 535–551 Wageningen, The Netherlands: International Society on Biotelemetry
    1. Louw G., Seely M.1982Ecology of desert organisms London, UK: Longman
    1. Mitchell D., Maloney S. K., Jessen C., Laburn H. P., Kamerman P. R., Mitchell G., Fuller A.2002Adaptive heterothermy and selective brain cooling in arid-zone mammals. Comp. Biochem. Physiol. B 131, 571–585 (doi:10.1016/S1096-4959(02)00012-X) - DOI - PubMed
    1. Pinheiro J., Bates D., DebRoy S., Sarkar D.The R Core Team 2007nlme: linear and nonlinear mixed effects models. R package version 3.1-86

Publication types

LinkOut - more resources