Final answer:
During hibernation, animals enter a state of inactivity with reduced metabolism to survive winter. Estivation is a similar state for surviving hot, dry summers. Daily torpor is a short-term energy conservation strategy used daily during the coldest parts.
Step-by-step explanation:
Understanding Hibernation, Estivation, and Daily Torpor
Hibernation is a state of inactivity and metabolic depression in endotherms, primarily observed during the winter months when food is scarce and temperatures are low. During hibernation, animals like ground squirrels can reach an abdominal temperature of 0° C (32° F), conserving energy and surviving on stored body fat. On the other hand, larger animals like bears maintain a higher body temperature, around 37° C (99° F), even though they undergo similar metabolic slowdown.
Estivation is similar to hibernation but occurs during the summer months in response to high temperatures and drought. This strategy is used by some desert animals to conserve water and reduce metabolic rate, helping them to survive the harshest conditions. For example, a lizard in estivation would become less active and its body would adjust to retain water and manage nitrogen waste efficiently.
Daily torpor is a short-term hibernation-like state that can occur daily, helping animals like bats and hummingbirds to conserve energy during colder parts of the day. This is especially important in smaller animals where endothermy is limited by their surface to volume ratio.