When you think of hibernation, bears and groundhogs slumbering throughout the winter likely come to mind. However, furry creatures aren't the only animals that take long rests, it doesn't only happen in the winter, and they're not just sleeping. During summer, some animals including reptiles, insects, and amphibians enter estivation, a period of extended torpor that occurs in hot months. Both hibernation and estivation are dormant states where an animal conserves energy by lowering its metabolic rate and body temperature.