Aestivation also aestivate. Although relatively uncommon, a small number of mammals aestivate. Animal physiologist Kathrin Dausmann of Philipps University of Marburg, Germany, and coworkers presented evidence in a 2004 edition of "Nature" that the Malagasy fat-tailed dwarf lemur hibernates or aestivates in a small tree hole for seven months of the year. According to the Oakland Zoo in California, East African hedgehogs are thought to aestivate during the dry season. Aestivation Aestivation or æstivation (from , summer, but also spelled estivation in American English) is a state of animal dormancy, similar to hibernation, characterized by inactivity and a lowered metabolic rate,
Hibernation their pre-hibernation weight by using their stored fats for energy. True hibernation is restricted to endotherms; ectotherms by definition cannot hibernate because they cannot actively down-regulate their body temperature or their metabolic rate. Still, many ectothermic animals undergo periods of dormancy which are sometimes confused with hibernation. Some reptile species are said to brumate, but possible similarities between brumation and hibernation are not firmly established. Many insects, such as the wasp "Polistes exclamans", exhibit periods of dormancy which have often been referred to as hibernation, despite their ectothermy. Obligate hibernators are animals that spontaneously, and annually, enter hibernation regardless of