Essay on Animal Behaviour | Wildlife | Geography

Here is an essay on ‘Animal Behaviour’ for class 6, 7, 8, 9, 10, 11 and 12. Find paragraphs, long and short essays on ‘Animal Behaviour’ especially written for school and college students.

Essay # 1. Inter and Intraspecific Relations:

Animal behaviour is related with the field of wildlife management. In each animal, there is basic drive through which it shows all types of behavioural responses resulting the survival of the animal. The survival of an animal depends upon the obtaining food, protection against adverse climate and to escape mortality from diseases, parasites and predators.

But the survival of animal populations depends upon the buildup of successful pair, birth of young ones and making them self-independent. Due to such basic drives, each species shows some specific pattern of behaviour which is characteristic of that species. The factors that affect an animal are called stimuli or agents that cause changes in the activity of the organisms and the changes are called responses.

The animal is constantly receiving stimuli from its environment and is continuously integrating and filtering those stimuli important at the time. Response is made to them in different ways. Stimuli may cause conflicting responses also such as when a prey sees predator, it has a tendency to remain hidden or to run-off.

Animals receive stimuli from their environment through several means including sound, sight, mechanical forces (touch) and chemicals (scent, taste, and internally secreted hormones).

Behavioural-Responses are of three kinds:

(i) Major Behavioural Response:

It is apparent to see such as run­off, fly-off, courtship, eating etc. of the animal. In such behaviour, the purpose of the animal is seen clearly and the response is resulted accordingly.

(ii) Minor Behavioural Response:

In such response, the animal is watched carefully. For example, keeping any part of the body (ear, tail, head etc.) in specific direction is the symbol of particular response.

(iii) Internal Behavioural Response:

Such response is due to chemical secretion inside the body such as hormone etc.

Environment has two components viz. abiotic (gases, water etc.) and biotic (plants and animals). Abiotic components of the environment influence the structural and behavioural characteristics of the animals, plants and other forms of life. Biotic factors are the results of interactions among the different organisms of the same or the different species.

In the ecosystem, no living organism can live in isolation and all the organisms are closely interlinked and interdependent on each other for obtaining the food, shelter, protection and other requirements.

Animals of one species are linked with animals of the same species or with the animals or plants of the different species and vice-versa. If the interrelationship or interaction is in between the organisms of same species, it is known as Intraspecific-relationship; and if among the organisms of different species, it is called as Interspecific-relationship.

The interspecific-relationship may be three kinds such as:

(a) Neutralism where none of the species are affected.

(b) Symbiosis where both the partners are benefited and neither species is harmed (further divided into Mutualism and Commensalisms), and

(c) Antagonism in which one or both the species are pitted against each other (divided into Antibiosis, Parasitism, Predation and Competition).

Intraspecific and interspecific relations may be classified into three categories:

(i) Competition:

Competition results when two animals are after the same component of their environment when the supply of that component is limited. Food and reproduction are the two main requirements of the animal. For these two needs, there is competition in the animals at different times.

As far as food is concerned, there is no competition in herbivorous animals neither interspecific nor intraspecific because they (cheetal, sambhar, blackbuck etc.;) graze together in herds and do not quarrel for food or move/migrate to other places in case of scarcity of the food.

But on the contrary in carnivores, the situation is different; when the food is limited, the largest strong and aggressive animal takes the food and the weaker ones is fled away by it as well as sometimes even kilted.

For example, tiger sometimes kills the panther to grab the prey hunted by the panther. The hiding of prey killed by tiger or panther is a kind of competition. Sometimes, the young tiger or lion is fled away by its own old parents in the scarcity of food.

Generally, after being satisfied, tiger/lion permit its species to take food from its killed prey. In breeding, there is great intraspecific competition. There is even fight among males to find estrus female and there are cases of blood shedding. Breeding-competition is useful as it gives chances to produce genetically improved offspring.

There is also competition among the animals for social hierarchy. For this, they show strongness. The length and size of horns and antlers are helpful in such cases, and if not decided, fighting occurs. In fowl, there is unique system to get social hierarchy. It is done by pecking. The strong fowl compels to surrender the weaker one by pecking. They are arranged serially according to strongness and called as Peck-order.

(ii) Co-Operation:

Co-operative relation is that in which the animal of the same species or different species co-operate among themselves. To make herd in herbivores is example of such relation. At the time of grazing herd of deer, one or two members remain alert by seeing to and fro to identify any type of danger and give signal to the whole herd to run and escape following them.

The co-operation between monkey and cheetal is famous in this regard. The herd of cheetal, graze beneath the tree upon which monkey is eating the fruits. The deer (cheetal) eat the unused fruit fallen on the ground. A part from this, the monkey even emits special sound to escape to the cheetals in case predators like tiger or panther is seen. Likewise, bird (mayna etc.) sitting on the back of cheetal eats ectoparasites.

(iii) Neutral Relation:

This is a relation in which a member has no relation with other members of the same species. But such relation is difficult in wild animals because this would seldom occur under natural conditions. Though, after mating season, male deer generally depart from the females, however, in that period also they form herd of some males. Hence, neutral-relation generally is not seen in nature.

In addition there are other types of behaviour such as Play-behaviour that is characteristics of most animals. Deer will frolic running in circles for no apparent reasons, butting heads and doing other things that have no apparent significance. Play is the most useful in establishing social bonds, teaching prey-capture techniques and effective copulation-postures. It is difficult to determine how important play is for survival but it is clearly a natural part of the life of many animals.

Thus the degree of competition, co-operation or neutrality between the animals depend on a number of factors, and the complexity of these factors in space and time indicates the dynamic character of wildlife- ecology. Home-range, territory etc. are the outcome of such relations.

Species whose populations are dwindling may ultimately reach an extinction-threshold, where a minimum number is required for survival. This is the biological minimum number. If this minimum number decreases below this extinction-threshold, the rebuilding of the species is impossible and extinction of the species results which is known as critical- limit for a particular species.

On contrast, if the number of a population is more than the carrying-capacity of the habitat or has obtained optimum-density or subsistence-density or has come to the stage of stability; their harvesting is very essential before/after reaching such stages for the proper growth of the species; otherwise, the individuals will either die through decimating factors of the environment or through the predators.

Such harvesting will enable the species for getting the chance to reach again to the balancing stage. Such surplus number of the population liable to harvest is called shootable-surplus.

Essay # 2. Prey & Predation (Prey & Predator Relationship):

The fundamental requirements of animal life are food, water and shelter and the satisfaction of the instinctive needs of the species in regard to the latter is the most important. For instance, some species of birds favour trees or short grasses while others favour high trees standing above the level of the main forest.

If this condition is not provided or if they are modified in some ways, as by allowing the grass to grow high or by removing the dominant trees, the particular species will shun the locality.

Plants through photosynthesis produce food material which is absorbed by animals that are plant eaters. These in turn, when they are preyed upon, by meat-eating animals, pass the energy on to the latter; generally from a smaller and more numerous preys to a larger and fiercer, though possibly less numerous, predator.

Exceptions in this regard are the wild dog and the wolf, which though small make up in fierceness and pack-strength enable them to overcome much larger prey and even the big carnivore. It is well known, for instance, that the tiger fears the wild dog. The series of energy-transfers is called food-chain because of the linkage of one to the other; food-chains rarely exceed four or five links and end in a predator which has no enemies.

The top link in a food-chain is generally controlled by territorial demands or requirements of space or territory for growth and development of the individual of the species and this territorial demand is strongest in predators. The several food-chains of an animal community constitute a food-web.

In an association, the elements are intimately connected and depend on one another. Destruction of the “balance” can be achieved by the destruction of one element and the same principle holds true for food-chains.

Snakes prey on the field rats which is an enemy of food- crops; the hawk attacks certain birds which live on spiders, which in turn live on aphids or plant lice which damage fruit trees. Thus, elimination of snake, hawk or other animals may start a chain-reaction which in the end recoils on man who is responsible for upsetting the “balance”.

Predator:

An animal which preys on other inferior or weaker animals, such phenomenon is called as predation.

Prey:

An inferior or weaker animal, which is preyed upon by a predator. An animal that may be seized by another to be devoured.

Predators have an important role in regulating “balance of nature”. Predator-prey relationship is intricate. When the number of prey of particular species starts downing, the predator starts to prey another prey species. Thus, the predation or the preying of one animal upon another for the sake of food is merely a step in the energy-cycle of food-chains.

Herbivores are excluded from it. If predation does not exist, the biological pressure or expansion of an organism would soon result in giving no room for other life. Biological-pressure is doomed to dissipation against environmental-resistance and the multiplication of a series is automatically controlled by predation and disease. Every species has both advantages which enable it to survive and weaknesses which permit other animals to exist.

Predation varies with the number of animals in excess of the capacity of the environment to support them that is with the fluctuation between biological-pressure and environmental-resistance. Predation- losses increase with the building-up of environmental resistance and decline with the decrease in environmental-resistance. The same holds good for changes in the biological-pressure.

Predation may be classified in the following types:

(i) Chance Predation:

It is casual and is of no importance. The prey species is temporarily at a disadvantage and is seized by a predator.

(ii) Habit Predation:

Under a stable habitat over a wide range, predators feed regularly on surplus individuals and this does not normally affect the population density.

(iii) Sanitary Predation:

When diseased, crippled, parasitized individuals are taken up by predators.

(iv) Sucker-List Predation:

When mentally and physically deformed individuals; are eliminated by predators.

When predation departs from the normal phenomenon of losses among the less vigorous and instead takes place among the more vigorous classes, a week-ness or breakdown of the environment is indicated, as if when only the best bulls are taken by a tiger.

The disturbing effects of predation are beneficial in that they force the prey-species to find a new and sometimes better range. They definitely contribute towards maintaining the vigours of the stock.

Upper-Limit & Lower-Limit:

The Upper-limit is the size of food that predators can normally eat and is determined by ability to overcome the prey. The Lower-limit of the food of a predator is the size below which the animal is not compensated for the time spent on predation.

The calorific value of individual foods has, in the process of evolution, determined the quantity of food eaten which in turn is adjusted to the size of animal, its activity and its metabolic make-up. Herbivorous foods have fewer calories than animal’s foods and therefore require a larger digestive system.

Bergmann Principle (Bergmann’s Rule):

The number of calories required varies with animal bulk. Cold-weather foods may be more concentrated and hot-weather foods more moisture-producing. Young animals require more food than adults and active animals require more than sluggish ones. There is a tendency towards increase of size in cold climates and in the same species the representative from a northern or colder climate will be smaller.

This is a reflex of the need for conservation and radiation of heat and is called as Bergmann Principle. Wild animals require several times the calorific requirements of man, which are about 15 to 20 calories per day for each pound of the body weight. The food requirements of the system of a particular species are adjusted to its digestive ability of its “instinctive selection pattern”.

It has been established that animals are able to recognize difference in foods. Hence, according to Bergmann’s rule, geographical races of a species inhabiting cold-region are much larger in size than the races inhabiting warmer-region.

This rule suggests that as the temperature decreases from the equator towards the poles, the body size of the individuals living there increases in size can be explained by considering that the larger animals have a less surface area per unit of weight than the smaller one and, therefore, the proportionate loss of heat by radiation is less than in smaller animals.

In animals living in warmer areas, the smaller size of the body is more suited to these animals. The rule is well supported by the wildlife found in cold and warmer areas. The largest bears are the polar bears found in far north, while the smaller black bears have a smaller size.

Principles of Predation:

The principles of predation may be stated as follows:

(i) The term predator does not necessarily denote a destructive animal.

(ii) Generally, predators live on annual surplus produced by a prey species.

(iii) Except in special circumstances, no predator except man is capable of exterminating a prey species.

(iv) The most destructive predators, when occurring only sparsely, can have little effect upon the total numbers of desirable prey species.

(v) A reduction in the number of predators on a given area does not necessarily mean a reduction in predator pressure on a specific prey animal.

(vi) Herbivorous animal population tends to increase towards self-destruction, if not held in check by various counterforces. For example, hoofed animals and rodents are inclined to overpopulate their habitat when effective controls are absent. The end result of this over-population is usually a “crash” brought on by starvation, disease or emigration.

Predation may be considered a beneficial service for most prey species of this type. Predators may be an important factor in the survival of some prey species.

(vii) The net effect of predation upon a particular prey species is measured, not in terms of its per cent occurrence in the predator’s diet, but rather in terms of number lost to predation in relation to the total population of the prey species.

(viii) Availability, above all else, governs the diet of the most predatory animals.

(ix) Predator-control may benefit a desired species on areas where other environmental conditions are favourable for increase, specially when the numbers of the prey species are well below the normal.

(x) The need or value of predator-control in game management is proportional to the intensity of the game-harvest.

Problems in Predator Control:

Problems in regard to predation and predator control are:

(i) There is a need for a proper definition of the word predator and a better identification of predators to be classified as truly destructive and requiring control.

(ii) Control efforts need to be specific for the target predator.

(iii) The cost of predator-control to protect livestock has often cost more than the livestock is worth.

(iv) Emphasis should be upon control or alleviation of the damage, rather than upon control of predators.

(v) There is a need for the recognition of the many values of the predators.

(vi) There is need to provide people with biological information concerning the benefits and values of predation and the need for caution and careful direction in control.

In nature, the biological-balance represents the evolutionary adjustment between breeding-potential and environmental-resistance. The breeding potential always tends to press upwards against environmental-resistance and it is normal for there to be a tendency towards increase in. population. Productivity tends to decrease with increase of abundance and to increase with decrease of numbers.