HOMEOTHERMS (ANIMALS): CHARACTERISTICS AND EXAMPLES - BIOLOGY - 2025

The warm - blooded animals are those who have the ability to maintain their body temperature relatively constant internal. The temperature of these animals is maintained regardless of the temperature variations of the environment that surrounds them. They are also known as warm-blooded or thermoregulatory animals.

This capacity is given by a process known as thermoregulation. Which allows them to maintain their body temperature in a range between 36 ° and 42 °, depending on the species to which the animal belongs.

Birds and mammals are the two large groups that make up this classification. In these animals, this capacity is essential for the development of a great variety of biochemical reactions and physiological processes that are related to the normal functioning of their metabolism and their survival.

Similarly, this ability also allows homeothermic animals to adapt to survive in geographic areas with extreme climates such as the poles and deserts.

The emperor penguin, for example, lives in Antarctica, where the temperature can drop to -60 ° C and the fennec (desert fox) lives in the deserts of the Sahara and Arabia, where the temperature reaches 59 ° C.

Thermoregulation process in homeothermic animals

Thermoregulation is the phenomenon by which homeotherms can keep their body temperature constant despite the thermal fluctuations of the environment in which they live.

This is produced through the balance between the production and loss of heat in the face of thermal stimuli from the environment. That is, it is the natural response of the animal's organism to the climatic demands of its habitat to maintain the adequate internal body temperature for its survival.

To achieve this balance, a high degree of energy consumption is required, which is possible thanks to the activation of different regulation mechanisms and a central control system. The regulatory mechanisms are of two types: detection mechanisms and response mechanisms.

The detection mechanisms are those that receive and send the information about temperature changes to the central control system. They are made up of peripheral nerve endings and sensing nerve points in the medulla and hypothalamus.

The central control system, for its part, is in charge of processing the information and generating the responses that will allow maintaining the vital body temperature of the animal. In homeothermic animals this function is fulfilled by the hypothalamus.

The response mechanisms are responsible for keeping the internal body temperature of the animal constant. They include the processes of thermogenesis (heat production) and thermolysis (heat loss). These mechanisms can be of two types: physiological and behavioral.

Depending on the species, homeotherms present a degree of body temperature considered normal (for example, for the polar bear 38 ° C, for the elephant 36 ° C, for most birds 40 ° C, etc).

This temperature is maintained at these levels thanks to the normal metabolic processes of the body. This is what is known as the thermoneutral temperature range.

However, when body thermal levels in these animals rise or fall to critical levels, special response mechanisms are activated that involve increasing the metabolic output ratio to generate heat or prevent heat loss.

Response mechanisms in thermoregulation

There are response mechanisms in thermoregulation that are common to all homeothermic animals, but some are specific to each species.

Many of them are manifested in the physiology or behavior of the animal (winter coat, hibernation, etc.). In general terms, these responses occur within two processes: thermal radiation and evaporation.

Interaction of the body with the environment

The first response consists in the interaction of the body with the environment or the organism with another object or body and allows both the production and loss of heat.

An example of this can be seen in the grouping of emperor penguins during the colder seasons. Joining together allows them to generate enough heat to keep internal body temperature at a neutral level, regardless of the extreme cold of the environment.

Another example is the coat of hair or plumage that some animals develop during the winter seasons and that allows them to withstand low temperatures (ptarmigan, wolves, etc.).

Perspiration

The second answer is related to the loss of heat through the evaporation of water through the pores of the skin (perspiration) or some other mechanism that allows the body to cool down.

For example, dogs perspire through their paw pads and use their tongues when panting to release heat. In the case of pigs, they roll in mud to cool off, because they have few sweat glands.

Other mechanisms of thermoregulation

• Piloerection or ptilerection. It is the erection of the hairs or feathers and occurs in cold situations in order to keep the air between the skin and the environment to generate an insulating barrier that prevents heat loss.
• Hibernation. It consists of a state of deep sleep in which the vital functions (respiration, heartbeat, temperature) of the animal are drastically reduced. The animal survives by consuming the caloric reserves stored during the periods of activity.
• Physiological changes. Variations in weight and change of coat or plumage during the different seasons of the year to adapt to the environmental temperature.

Examples of homeothermic animals

Elephant

Due to its large size, the elephant generates large amounts of heat. In order to keep its body temperature stable and release heat, the elephant uses its ears.

Elephants can't sweat, so they wiggle their ears to cool off. When moved, the blood vessels dilate or contract at will, promoting the cooling of the blood in this area, to then be dispersed throughout the body and thus cool it.

The structure of their skin also allows them to regulate heat. The deep cracks and channels in the skin that trap moisture and the tiny bristles that generate tiny air currents help maintain the animal's body temperature.

The polar bear

This animal, whose habitat has temperatures that can reach -30 ° C, maintains its constant internal body temperature thanks to its extensive layers of skin, fat and fur.

The camel

The camel has thermoregulatory mechanisms related to its physiognomy. Its long legs and long neck give it the height necessary to increase its cooling possibilities.

In addition, their fur, which is a kind of fluff, helps them insulate their skin from environmental heat. Similarly, the fact that most of your body fat is stored in your humps and not between your skin and muscles, allows you to take better advantage of the ambient air to cool yourself.

References

1. Guarnera, E. (2013). Essential aspects of the interface of parasitic zoonoses. Dunken Publishing House: Buenos Aires. Recovered at: books.google.co.ve.
2. Pandey and Shukla (2005). Regulatory Mechanism in Vertebrates. Rastogi Publications: India Retrieved from: books.google.es.
3. González J. (s / f). Heat stress in bovines. Bovine Welfare. Recovered at: produccionbovina.com.
4. Physiological, Behavioral and Genetic Responses to the Thermal Environment. Chapter 14 in Responses to the Thermal Environment. Recovered at: d.umn.edu.
5. Alfaro et al. (2005). Animal physiology. Editions of the University of Barcelona: Spain. Recovered at: books.google.es.
6. Scanes, C. (2010). Fundamentals of Animal Science. Delmar Cengage Learning. Recovered at: books.google.co.ve.
7. González M (s / f). Dumbo is on fire, or on elephant heat transfer. Physics II Sigman Chair - UBA. Recovered at: users.df.uba.ar.