Adaptations to environment in the mountain hare (Lepus timidus): thermal physiology and histochemical properties of locomotory muscles
| Autor: | S. Sulkava, Raimo Hissa, Ahti Putaala, A. Pyörnilä |
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| Rok vydání: | 1992 |
| Předmět: | |
| Zdroj: | Canadian Journal of Zoology. 70:1325-1330 |
| ISSN: | 1480-3283 0008-4301 |
| DOI: | 10.1139/z92-186 |
| Popis: | Oxygen consumption of mountain hares (Lepus timidus) subjected to different ambient temperatures was measured. The basal metabolic rate was 3.91 ± 0.05 W∙kg−1 in winter and 4.75 ± 0.06 W∙kg−1 in summer. These values are 162 and 186% of the weight specific values, respectively. Minimum thermal conductances (winter, 0.076 ± 0.017 W∙kg−1∙°C−1; summer, 0.141 ± 0.018 W∙kg−1∙°C−1) were 74 and 134% of the values predicted from body weight, respectively. It appears that adaptation of the mountain hare to winter is largely based on insulation. The fibre type composition of a flexor and an extensor muscle in the hindlimb was studied from sections stained for succinate dehydrogenase and myosin adenosine triphosphatase. More than 60% of the cells were fast-twitch oxidative glycolytic fibres, and 30–40% were fast-twitch glycolytic fibres. The greatest difference between the muscles was in the relative number of the slow-twitch oxidative fibres, with the flexor containing 13.7 and the extensor 2.9% of this fibre type. The histochemical properties of the muscles studied are consistent with the locomotory pattern of the mountain hare, which is characterized by darting or sprinting movements, and endurance in flight run. |
| Databáze: | OpenAIRE |
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