Behavioural adaptations
In the environment the ectotherm live they will actively seek
out an area for obtaining external heat or a place to shelter from the heat:
for example the Komodo dragon (Varanus komodoensis), it is found on a hand full
of islands in the Indonesian archipelago, these reptiles rely on the heat of
the sun in the morning to regulate their body temperature, in the morning the animal
will find a place where it can out stretch, perpendicular to the direction of
the sun, there it will remain basking
until its body temperature is increased to roughly to the ambient temperature
of the environment (Park, n.d.),
if the dragon find the ambient temperature is too warm, subsequently the dragon
becomes too hot risking dehydration it will dig out a den to protect itself
from the heat and the sun. (Dang, 2007). Many reptiles will have to become dormant during the hottest part of the
summer as a reptile can tolerate cold temperature much better than they can the
hot temperature. When the reptile becomes dormant in the summer months
(aestivation) the physiology of this summer dormancy is very different to that
of the winter dormancy (winter dormancy is a state of torpor disguised below).
During the heat the reptile must find a cool shady place to remain
physiologically active, however at this time they must forfeit the all their
normal activity as the cooler temperature will restrict their ability to behave
normally.
Another avoidance adaptation which animal use is hibernation this is a state of inactivity and metabolic depression. Of which there are two groups the Obligate hibernator’s (animals which spontaneously hibernate annually regardless of ambient temperature or food availability) examples ground squirrel, rodents, European Hedgehog (,Erinaceus europaeus) insectivores, monotremes (mammals who lay eggs), marsupials (pouched animals) and the small tortoiseshell butterfly (Aglais urticae). And the Facultative hibernators (hibernation occurs due to cold, stress, food deprivation or both) examples of some of the species are prairie dog (Cynomys), bears, the white (Cynomys leucurus) and black (Cynomys ludovicianus) tailed prairie dogs.
In the endothermic species, it is a season or time period which is called heterothermy (animals who have the ability to switch between ectothermic (or poikilothermic) and endothermic (or homoeothermic) strategies).
These changes can are generally used to dissociate the fluctuating metabolic rates of the animals, it occurs in mammals such as the bear species bats, hummingbirds, and many ectothermic animals. (Mayer, 2014)
The hibernation of an animal involves firstly storing up enough energy to last them through the period of hibernation (entire winter). The larger species will become Hyperphagic and consume large amounts of food storing as energy in fat deposits, in the smaller species they will replace becoming fat with food caching. Then as the environmental temperature drops, their body temperature becomes lowered slowing their breathing down, heart rate, and oxygen consumption, the now achieved low metabolic rate, is mediated by a pert of the animal nervous system.
True hibernation requires internal organs like the digestive tract and endocrine system to almost shut down this places a great strain on the animals tissues as they are all directed toward maintaining the metabolism at its most basic (just sustaining life) even the bones and teeth will deteriorate during the hibernation period, hibernators do not stay in this state constantly for the time it hibernates(in most animals it is the coldest times from the beginning of winter to the spring) the arousal periods are more frequent during the beginning and the end of the hibernation period than in the middle. (Mayer, 2014)
Animals who hibernate can be place in to four separate groups depending on how they begin the hibernation period: (Mayer, 2014)
The temperature of the bear: the normal temperature of the bear is 38 0C (1000F) drops during the winter sleep to about 340C (930F) its temperature will seldom drop below 310C (88.20F). (Mayer, 2014) (Hellgren, 1998)
Other mammals who winter sleep as opposed to hibernate, the chipmunk (Eutamias), the raccoons (Procyon lotor )and bear, the winter sleep instead of hibernation will save the animal the high energy cost and stress of the true hibernation, this additionally means the animal can conserve food, while still having the ability to avoid predation. (Mayer, 2014) (Humphries, et al., 2003)
It is not only the endotherms who will avoid the extreme temperatures, lack of food, and lack of water, by going in to a hibernation state most species of poikilothermous animals do due to the fact that there body temperature is regulated by the outside environment. (Mayer, 2014)
Another avoidance adaptation which animal use is hibernation this is a state of inactivity and metabolic depression. Of which there are two groups the Obligate hibernator’s (animals which spontaneously hibernate annually regardless of ambient temperature or food availability) examples ground squirrel, rodents, European Hedgehog (,Erinaceus europaeus) insectivores, monotremes (mammals who lay eggs), marsupials (pouched animals) and the small tortoiseshell butterfly (Aglais urticae). And the Facultative hibernators (hibernation occurs due to cold, stress, food deprivation or both) examples of some of the species are prairie dog (Cynomys), bears, the white (Cynomys leucurus) and black (Cynomys ludovicianus) tailed prairie dogs.
In the endothermic species, it is a season or time period which is called heterothermy (animals who have the ability to switch between ectothermic (or poikilothermic) and endothermic (or homoeothermic) strategies).
These changes can are generally used to dissociate the fluctuating metabolic rates of the animals, it occurs in mammals such as the bear species bats, hummingbirds, and many ectothermic animals. (Mayer, 2014)
The hibernation of an animal involves firstly storing up enough energy to last them through the period of hibernation (entire winter). The larger species will become Hyperphagic and consume large amounts of food storing as energy in fat deposits, in the smaller species they will replace becoming fat with food caching. Then as the environmental temperature drops, their body temperature becomes lowered slowing their breathing down, heart rate, and oxygen consumption, the now achieved low metabolic rate, is mediated by a pert of the animal nervous system.
True hibernation requires internal organs like the digestive tract and endocrine system to almost shut down this places a great strain on the animals tissues as they are all directed toward maintaining the metabolism at its most basic (just sustaining life) even the bones and teeth will deteriorate during the hibernation period, hibernators do not stay in this state constantly for the time it hibernates(in most animals it is the coldest times from the beginning of winter to the spring) the arousal periods are more frequent during the beginning and the end of the hibernation period than in the middle. (Mayer, 2014)
Animals who hibernate can be place in to four separate groups depending on how they begin the hibernation period: (Mayer, 2014)
- The animal will wait a period of time during
the start of the cold temperatures (1-3 months) and then enters hibernation in
one major temperature reduction, accomplished only when biochemical and
physiological preparations have been enough to prompt the hibernation stimulus,
causing the abandonment of the temperature differential between the ambient (environment)
and body temperature. An example of this is the golden hamster (Mesocricetus
auratus) (Mayer, 2014)
- This group will prepare for hibernation only
waiting a few days in to the cold weather before becoming torpid in one major
temperature decline, the Rock pocket mouse (Chaetodipus intermedius) is a
member of the group of animals who exhibit this form of hibernation. (Mayer, 2014)
- A group that most of the mammalian hibernator’s
belong to, they will wait only a matter of days before they go through a series
of steps where they enter torpid and arousal, each one at successively lower
body temperature, until the level dictated by the stage or preparation for
hibernation is reached, in this group there are the California ground squirrel (Otospermophilus
beecheyi) and the marmots (Marmota). (Mayer, 2014)
- In this group the animals become inactive in
the poikilothermous manner (temperature follows the ambient temperature) bats
are an example of this group. (Mayer, 2014)
The temperature of the bear: the normal temperature of the bear is 38 0C (1000F) drops during the winter sleep to about 340C (930F) its temperature will seldom drop below 310C (88.20F). (Mayer, 2014) (Hellgren, 1998)
Other mammals who winter sleep as opposed to hibernate, the chipmunk (Eutamias), the raccoons (Procyon lotor )and bear, the winter sleep instead of hibernation will save the animal the high energy cost and stress of the true hibernation, this additionally means the animal can conserve food, while still having the ability to avoid predation. (Mayer, 2014) (Humphries, et al., 2003)
It is not only the endotherms who will avoid the extreme temperatures, lack of food, and lack of water, by going in to a hibernation state most species of poikilothermous animals do due to the fact that there body temperature is regulated by the outside environment. (Mayer, 2014)