Temperature regulation of the testes of the bottlenose dolphin (Tursiops truncatus): evidence from colonic temperatures
Dolphins possess a countercurrent heat exchanger that functions to cool their intra-abdominal testes. spermatic arteries in the posterior abdomen are juxtaposed to veins returning cooled blood from the surfaces of the dorsal fin and flukes. A rectal probe housing a linear array of five copper-constantan thermocouples was designed to measure colonic temperatures simultaneously at positions anterior to, within, and posterior to the region of the colon flanked by the countercurrent heat exchanger. Colonic temperatures adjacent to the countercurrent heat exchanger were maximally 1.3°C cooler than temperatures measured outside this region. Temporary heating and cooling of the dorsal fin and flukes affected temperatures at the countercurrent heat exchanger, but had little or no effect on temperatures posterior to its position. These measurements support the hypothesis that cooled blood is introduced into the deep abdominal cavity and functions specifically to regulate the temperature of arterial blood flow to the dolphin testes.
Key wordsThermoregulation Countercurrent heat exchange Testis Clinical assessment Dolphin, Tursiops
countercurrent heat exchanger
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- Bedford JM (1977) Evolution of the scrotum: the epididymis as the prime mover? In: Calaby JH, Tyndale-Biscoe CH (eds) Reproduction and evolution. Australian Academy of Science, Canberra City, pp 171–182Google Scholar
- Carrick FN, Setchell BP (1977) The evolution of the scrotum. In: Calaby JH, Tyndale-Biscoe CH (eds) Reproduction and evolution. Australian Academy of Science, Canberra City, pp 165–170Google Scholar
- Cowles RB (1958) The evolutionary significance of the scrotum. Evolution 12:417–418Google Scholar
- Fish FE, Hui CA (1991) Dolphin swimming — a review. Mammal Rev 21:181–195Google Scholar
- Geraci JR (1981) Marine mammal care. Univ. of Guelph, OntarioGoogle Scholar
- Hampton IFG Whittow GC (1976) Body temperature and heat exchange in the Hawaiian spinner dolphin, Stenella longirostris. Comp Biochem Physiol 55A:195–197Google Scholar
- McGinnis SM, Whittow GC, Ohata CA, Huber H (1972) Body heat dissipation and conservation in two species of dolphins. Comp Biochem Physiol 43A:417–423Google Scholar
- Ridgway SH (1972) Homeostasis in the aquatic environment. In: Ridgway SH (ed) Mammals of the sea: biology and medicine. Thomas, Springfield, pp 590–747Google Scholar
- Schmidt-Nielsen K (1990) Animal physiology: adaptation an environment, 4th edn. Cambridge Univ Press, New YorkGoogle Scholar
- VanDemark NL, Free MJ (1970) Temperature effects. In: Johnson AD et al. (eds) The testis, vol III. Academic Press, New York, pp 233–312Google Scholar
- Waites GMH (1970) Temperature regulation and the testis. In: Johnson AD et al. (eds) The testis, vol I. Academic Press, New York, pp 241–279Google Scholar