Hibernation patterns and energy expenditure in hedgehogs from semi-arid and temperate habitats

Abstract

Hibernation patterns, body temperature (Tb) and oxygen consumption (\(\dot V_{O_2 } \)) were measured during hibernation in two hedgehog species, a desert speciesHemiechinus auritus (body mass 367 g) and a temperate habitat speciesErinaceus europaeus (body mass 598 g). A continuous ambient temperature of 11 °C was the only necessary condition for both species to enter hibernation outdoors and in the laboratory. At this temperature, hibernation could be induced at any time of the year. Hibernation bouts ofHemiechinus were regular and short (average 4.8 days), whereas those ofErinaceus lasted 5 to 27 days (average 9.3 days). The frequency of spontaneous arousals was 5.3 and 2.9 per month forHemiechinus andErinaceus, respectively. None of the hedgehogs took any food during arousal periods. Both species had the sameTb during hibernation (12.5 °C) and during arousal (33 °C).\(\dot V_{O_2 } \) of the hibernatingHemiechinus was twice the rate ofErinaceus (0.050 vs. 0.025 ml g−1 h−1), but during arousal it was the same for both. The monthly average energy expenditure for both species was 1,477 kJ per animal, which is 15% of the energy used by non-hibernating hedgehogs. The corresponding amount of fat catabolized was 37 g per month. This mass loss would limit the hibernation inHemiechinus to 3.9 months and inErinaceus to 6.5 months. Although hibernation inHemiechinus does not constitute a special adaptation to hot environments, it significantly improves the hedgehog's energy economy during the desert winter.