Torpor
Encyclopedia
Torpor, sometimes called temporary hibernation 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 torpor include birds (even tiny hummingbirds, notably Cypselomorphae
) and some mammals such as mice
and bat
s. During the active part of their day, animals that undergo daily torpor maintain normal body temperature and activity levels, but their temperature drops during a portion of the day (usually night) to conserve energy. Torpor is often used to help animals survive during periods of colder temperatures, as it allows the organism to save the amount of energy that would normally be used to maintain a high body temperature.
Torpor may extend for a longer period of time. Some animals such as groundhog
s, ground squirrel
s and jumping mice enter this intensely deep state of hibernation
for the duration of the winter. Lungfish
switch to the torpor state if their pool dries out; tenrecs
switch to the torpor state if food is scarce during the summer in Madagascar. This prolonged and deep torpor during summer months is known as aestivation
. Black bears, although often thought of as hibernators, do not truly enter a state of torpor: while their body temperatures lower along with respiration and heartbeat, they do not decrease as significantly as most animals in a state of torpor, and bears are still responsive. 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.
Bats, especially species in temperate regions suffering harsh winters, rely upon torpor to survive. Lowering the body temperature to the ambient temperature allows them to enter torpor for prolonged periods at a lower metabolic cost. Oxygen consumption, heart rate and breathing rates are all lowered significantly meaning less energy is required to survive. Torpor is important in daily cycles to conserve energy as well as prolonged torpor, or hibernation. Pre-hibernation feeding builds up layers of fat which are used as the energy source during torpor. Arousal from torpor in bats is facultative
, not obligate
, but comes at a high energy cost, meaning awakening must be for a good reason.
In Buddhism torpor is one of the Five Hindrances
.
Metabolism
Metabolism is the set of chemical reactions that happen in the cells of living organisms to sustain life. These processes allow organisms to grow and reproduce, maintain their structures, and respond to their environments. Metabolism is usually divided into two categories...
. Animals that go through torpor include birds (even tiny hummingbirds, notably Cypselomorphae
Cypselomorphae
Cypselomorphae is a clade of birds. It includes the living families and orders Caprimulgidae , Nyctibiidae , Apodiformes , as well as the Aegotheliformes whose distinctness was only recently realized...
) and some mammals such as mice
MICE
-Fiction:*Mice , alien species in The Hitchhiker's Guide to the Galaxy*The Mice -Acronyms:* "Meetings, Incentives, Conferencing, Exhibitions", facilities terminology for events...
and bat
Bat
Bats are mammals of the order Chiroptera "hand" and pteron "wing") whose forelimbs form webbed wings, making them the only mammals naturally capable of true and sustained flight. By contrast, other mammals said to fly, such as flying squirrels, gliding possums, and colugos, glide rather than fly,...
s. During the active part of their day, animals that undergo daily torpor maintain normal body temperature and activity levels, but their temperature drops during a portion of the day (usually night) to conserve energy. Torpor is often used to help animals survive during periods of colder temperatures, as it allows the organism to save the amount of energy that would normally be used to maintain a high body temperature.
Torpor may extend for a longer period of time. Some animals such as groundhog
Groundhog
The groundhog , also known as a woodchuck, whistle-pig, or in some areas as a land-beaver, is a rodent of the family Sciuridae, belonging to the group of large ground squirrels known as marmots. Other marmots, such as the yellow-bellied and hoary marmots, live in rocky and mountainous areas, but...
s, ground squirrel
Round-tailed Ground Squirrel
The round-tailed ground squirrel , known as "Ardillón cola redonda" in Spanish, live in the desert of the Southwestern United States and adjacent Mexico. They are called "ground squirrels" because they burrow in loose soil, often under mesquite trees and creosote bushes.-Characteristics:Most...
s and jumping mice enter this intensely deep state of hibernation
Hibernation
Hibernation is a state of inactivity and metabolic depression in animals, characterized by lower body temperature, slower breathing, and lower metabolic rate. Hibernating animals conserve food, especially during winter when food supplies are limited, tapping energy reserves, body fat, at a slow rate...
for the duration of the winter. Lungfish
Lungfish
Lungfish are freshwater fish belonging to the Subclass Dipnoi. Lungfish are best known for retaining characteristics primitive within the Osteichthyes, including the ability to breathe air, and structures primitive within Sarcopterygii, including the presence of lobed fins with a well-developed...
switch to the torpor state if their pool dries out; tenrecs
Tenrecidae
Tenrecidae is a family of mammals found on Madagascar and parts of Africa. Tenrecs are widely diverse, resembling hedgehogs, shrews, opossums, mice and even otters, as a result of convergent evolution. They occupy aquatic, arboreal, terrestrial and fossorial environments...
switch to the torpor state if food is scarce during the summer in Madagascar. This prolonged and deep torpor during summer months is known as aestivation
Estivation
Aestivation is a state of animal dormancy, characterized by inactivity and a lowered metabolic rate, that is entered in response to high temperatures and arid conditions...
. Black bears, although often thought of as hibernators, do not truly enter a state of torpor: while their body temperatures lower along with respiration and heartbeat, they do not decrease as significantly as most animals in a state of torpor, and bears are still responsive. 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.
Bats, especially species in temperate regions suffering harsh winters, rely upon torpor to survive. Lowering the body temperature to the ambient temperature allows them to enter torpor for prolonged periods at a lower metabolic cost. Oxygen consumption, heart rate and breathing rates are all lowered significantly meaning less energy is required to survive. Torpor is important in daily cycles to conserve energy as well as prolonged torpor, or hibernation. Pre-hibernation feeding builds up layers of fat which are used as the energy source during torpor. Arousal from torpor in bats is facultative
Facultative
Facultative means "optional" or "discretionary" , used mainly in biology in phrases such as:* Facultative anaerobe, an organism that can use oxygen but also has anaerobic methods of energy production...
, not obligate
Obligate
Obligate means "by necessity" and is used mainly in biology in phrases such as:* Obligate aerobe, an organism that cannot survive without oxygen* Obligate anaerobe, an organism that cannot survive in the presence of oxygen...
, but comes at a high energy cost, meaning awakening must be for a good reason.
Other uses of the word
Torpor is alternatively used as a reference to any non-physiological state of inactivity. As an example, recently naturalists have learned that female crocodiles enters a deep torpor without aggression during their short egg laying period.In Buddhism torpor is one of the Five Hindrances
Five hindrances
In Buddhism, the five hindrances are negative mental states that impede success with meditation and lead away from enlightenment...
.