Physiology of Northern and Southern Musk Turtles (Sternotherus odoratus) during Simulated Hibernation

• Published in: Physiological zoology 1994-01, Vol.67 (1), p.263-281
• Main Authors: Ultsch, Gordon R., Cochran, Bradley M.
• Format: Article
• Language: English
• Subjects: Animals; Anoxia; Biological and medical sciences; Blood plasma; Chrysemys picta; Clines; Freshwater; Fundamental and applied biological sciences. Psychology; Hematocrit; Hibernation; Lactates; Sternotherus odoratus; Thermoregulation. Hibernation. Estivation. Ecophysiology and environmental effects; Turtles; Vertebrates: anatomy and physiology, studies on body, several organs or systems; Viability
• ISSN: 0031-935X; 1937-4267
• DOI: 10.1086/physzool.67.1.30163846

We have studied the physiology of musk turtles (Sternotherus odoratus) from the north-central United States during prolonged submergence (25 d) at 3° C in anoxic and normoxic water, conditions simulating the range of potential respiratory microenvironments during hibernation. We compare the results to earlier studies of musk turtles from central Alabama and to those of northern and southern painted turtles (Chrysemys picta). The acid-base status of anoxic northern musk turtles deteriorated slightly more rapidly than that of southern ones, the fall in plasma pH of southern turtles lagging by about 5 d. The northern turtles exhibited slouwer rates of decline of plasma [Na⁺] and [Cl⁻], indicating a better ability to maintain ion balance. The two effects seemed to be counterbalancing in that there was no difference in survival times in anoxic water between the two groups, although survival in normoxic water can reach at least 150 d in both. There was no physiological cline in survival during prolonged cold anoxic submergence among musk turtles, in contrast to painted turtles. Musk turtles from a gizven area are much less tolerant of submergence anoxia than painted turtles from the same area. We suggest that musk turtles may not be able to survive prolonged submergence in mud during hibernation. The difference in the physiology of the two species may be explained provisionally by considerations of historical ecology.