Thermoregulation - how does animals thermoregulate?

Thermoregulation

Thermoregulation is the maintenance of internal temperature of body. This article is all about thermoregulation and its importance.

Definition of Thermoregulation:

The ability of an organism to maintain its body temperature within certain specific limits despite fluctuations in its environment is called thermoregulation.

The organisms which keep their body temperature same as the temperature of their environment and avoid any kind of internal thermoregulation, are known as Thermo conforming organisms. Thermoregulation is a part of homeostasis which is the maintenance of internal body conditions despite changes in external environment. It is a state of dynamic equilibrium of internal body conditions.

Hyperthermia:

Hyperthermia occurs when internal body temperature exceeds its normal range. Human beings can also have lethal hyperthermia when their body temperature exceeds 35ºC or 95ºF for 6 hours. 

Hypothermia:

On contrary if body temperature falls below the normal range, the condition is known as hypothermia. When homeostatic control mechanism of heat malfunctions, it results in loss of body heat in spite of its production. Normal body temperature of human body is about 37ºC or 99ºF. When our body temperature decreases below 35ºC or 95ºF, it causes hypothermia. Its common cause is exposure to cold temperatures. Its treatment includes the common methods through which body temperature can be increased.

Some animals also undergo hibernation, torpor, aestivation, etc,.

To read more about it visit 

Hibernation, Aestivation, Torpor, and Denning

Classification of animals on the basis of thermoregulation 

Ectotherms:

Ectotherms regulate their internal body temperature by using external sources. These are also known as cold blooded animals. They also maintain their internal body temperature in narrow ranges in the same way as endotherms do. 

Example of ectotherms

Reptiles, amphibians, invertebrates, and fishes are included in this category.

Thermoregulation in ectotherms

In spite of maintaining their internal body temperature by using metabolic heat, they prefer to live in the environment having low to negligible changes in temperature. Tropics and oceans are common examples of such environments. Thus, ectotherms have developed various behavioral mechanisms to respond to any changes in their environment. For example, they may take sun bath to  increase their body temperature and seek shady places to decrease their body heat.

Thermoregulation mechanisms to reduce body heat

Ectotherms use various methods for thermoregulation. They may loose their body heat through Vaporization which is the process of evaporation of sweat and other body fluids.

Some ectotherms increase their blood flow to their skin to dissipate most of their energy and lower their body temperature, this phenomenon is known as convection.

Sometimes, to lose the body heat, ectotherms come in contact with colder surfaces like covering their selves with mud, Staying in water like that of river, pond, or lake, or lying in cool shady places. This phenomenon is called conduction.

Sometimes, ectotherms release their body heat by radiating it directly out of their body, this phenomenon is called radiation.

Thermoregulation mechanisms to increase body heat

In the same way, to increase the body temperature, ectotherms use following mechanism;

Conduction: 

In this method, they increase their body temperature by directly lying on hot surfaces, like sun bathing.

Convection:

In this phenomenon they may climb up higher surfaces like tree tops or high above on the mountains to get direct heat energy from the sun. Some organism may also enter hot water and air currents while some build insulating nests. All these methods help to increase their body temperature externally.

Insulation:

In this method, the organisms alter their surface to volume ratio by inflating their body to get more heat.

Radiation:

In this method, ectotherms get heat energy directly from the radiations. They lie in the sun, enfold their body to reduce exposure to prevent loss of body heat, and conceal or expose their wing surfaces according to their need.

Endotherms:

The animals which can produce internal body heat through metabolism, are known as endotherms. These are also called warm blooded animals. 

Examples of endotherms

Birds sand mammals are placed under this category.

Thermoregulation in endotherms

They maintain their internal body temperature despite fluctuations in the temperature of their environment. If the temperature in their environment decreases, they maintain their internal body temperature in narrow ranges by producing heat through metabolism. The reason behind the production of heat through metabolism is the greater number f mitochondria in endotherms than ectotherms. When more heat is needed, they simply increase their rate of metabolism of sugars, fats, etc.

Evaporation:

If the body temperature increases, evaporation through respiratory surfaces and sweat glands help to cool the body and keep the body temperature at equilibrium.

Panting:

The animals having fur on their bodies have less ability of sweating and evaporation through skin surfaces. So evaporation occurs on wet surfaces of mouth, tongue, and lungs. this phenomenon is called panting. Mammals like pigs, dogs, and cats rely on panting to loose the  excessive body heat. Such animals have sweat glands on their paw pads and snout. This sweating on the lower surface of their paws also provide them friction.

Gular fluttering:

To avoid hyperthermia, birds open their mouth/beak, increase blood flow towards their buccal cavity, and vibrate their gular. 

In low temperatures, Birds survive by a mechanism of Down feathers, these down feathers are able to trap warm air which acts as a very good insulator and prevent the heat loss from the body.

Mammals have fur on the skin and a thick layer of fat under their skin which insulates their body and prevent heat loss. Marine and polar mammals, which live in very cold environments, have a very thick layer of fat under their skin, called blubber. It is found in polar bears and whales.