<unk>  is a (usually short-term) state of decreased physiological activity in an animal, usually characterized by a reduced body temperature and rate of metabolism. Animals that go through<unk>  include birds (even tiny hummingbirds) - notably Cypselomorphae - and some small mammals such as bats. During the active part of their day, these animals maintain normal body temperature and activity levels, but their body temperature drops during a portion of the day (usually night) to conserve energy.<unk>  is often used to help animals survive during periods of colder temperatures, since it allows the organism to save the amount of energy that would normally be used to maintain a high body temperature.<unk>  may extend for a longer period of time. Some animals such as groundhogs, chipmunks, ground squirrels and jumping mice enter this intensely deep state of hibernation for the duration of the winter. Lungfish switch to the<unk>  state if their pool dries out; tenrecs switch to the<unk>  state if food is scarce during the summer (in Madagascar). Black bears, although often thought of as hibernators, do not truly enter a state of<unk> : While their body temperatures lower along with respiration and heartbeat, they do not decrease as significantly as most animals in a state of<unk> . Still, there is much debate about this within the scientific community: Some feel that black bears are true hibernators that employ a more advanced form of hibernation.
Torpor
Mourning
Bedwetting
Seafood
Rattlesnake
Electric shock
Burping
Hypnic jerk