Aestivation
From Wikipedia, the free encyclopedia
(Redirected from Estivation)
Aestivation (from Latin aestas, summer, but also spelled "estivation" in the USA)
is a state of animal dormancy,
that is entered in response to high temperatures
and arid conditions.[2] It takes place during times of heat and dryness,
the hot dry season, which is often
but not necessarily the summer months.[citation needed]
Invertebrate and vertebrate animals are known to enter this state
to avoid damage from high temperatures and
the risk of desiccation. Both terrestrial and aquatic
animals undergo aestivation.[citation needed]
Torpor
From Wikipedia, the free encyclopediarely upon torpor to survive. | Look up torpor in Wiktionary, the free dictionary. |
Torpor, sometimes called temporary hibernation[1] 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
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 groundhogs, ground squirrels
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.[3] 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.[citation needed]
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.
Dormancy
From Wikipedia, the free encyclopedia
to low temperatures that slow chemical activity.[1]
From Wikipedia, the free encyclopedia
Diapause
Dormancy is a period in an organism's life cycle when growth, development,
and (in animals) physical activity
are temporarily stopped. This minimizes metabolic activity and therefore
helps an organism to conserve energy.
Dormancy tends to be closely associated withenvironmental conditions.
Organisms can synchronize entry to a
dormant phase with their environment through predictive or consequential means.
Predictive dormancy occurs
when an organism enters a dormant phase before the onset of adverse conditions.
For example, photoperiod and
decreasing temperature are used by many plants to predict the onset of winter.
Consequential dormancy occurs
when organisms enter a dormant phase after adverse conditions have arisen.
This is commonly found in areas with
an unpredictable climate. While very sudden changes in conditions may lead
to a high mortality rate among animals
relying on consequential dormancy, its use can be advantageous,
as organisms remain active longer and are
therefore able to make greater use of available resources.
Brumation
Dormancy in reptiles is an example of brumation, which is similar to hibernation.[2][3] It differs from hibernation in the metabolic processes involved.[4]
Reptiles generally begin brumation in late fall (more specific times depend on the species). They will often wake up to drink water and return to "sleep". They can go months without food. Reptiles may want to eat more than usual before the brumation time but will eat less or refuse food as the temperature drops. However, they do need to drink water. The brumation period is anywhere from one to eight months depending on the air temperature and the size, age, and health of the reptile. During the first year of life, many small reptiles do not fully brumate, but rather slow down and eat less often. Brumation should not be confused with hibernation; when mammals hibernate, they are actually asleep; when reptiles brumate, they are less active, and their metabolism slows down so they just do not need to eat as often. Reptiles can often go through the whole winter without eating. Brumation is triggered by cold weather, lack of heat, and the decrease in the amount of hours of daylight in the winter.
From Wikipedia, the free encyclopedia
Diapause is a predictive strategy that is predetermined by an animal's genotype.
Diapause is common in insects, allowing them to suspend development between autumn and spring,
and in mammals such as the roe deer (Capreolus capreolus, the only ungulate with embryonal diapause),
where a delay in attachment of the embryo to the uterine lining ensures that offspring are born in spring,
when conditions are most favorable.
Embryonic diapause is also known as delayed implantation.
Hibernation
Hibernation is a mechanism used by many animals to escape cold weather and food shortage over the winter. Hibernation may be predictive or consequential. An animal prepares for hibernation by building up a thick layer of body fat during late summer and autumn that will provide it with energy during the dormant period. During hibernation, the animal undergoes many physiological changes, including decreased heart rate (by as much as 95%) and decreased body temperature. Animals that hibernate include bats, ground squirrels and other rodents, mouse lemurs, the European Hedgehog and other insectivores, monotremes and marsupials.
