May 8, 2018 Off By Free Online Notes

What is Behaviour? Behaviour is defined as a change in response to the stimulus. In other words, animal behavior is the sum of everything that animals do, i.e. flying, walking, sitting, sleeping, eating, mating, rearing young ones, etc. Let’s discuss various types of behaviour are as under;


Behaviour is divided into two main types;

  • innate behaviour
  • learned behaviour


It is a collection of responses that are predetermined by the inheritance of specific nerve or cytoplasmic pathways in multicellular or unicellular organisms. As a result of the built-in pathways, a given stimulus would produce invariably the same response. All plant behaviour is.innate.

Refined over many generations: These behaviour patterns have been developed and refined over many generations (selected) and their primary adaptive significance lies in their survival value to the species.

Economy: Another feature is the economy it places on nerve pathways within multicellular organisms since it does not demand the higher center of the nervous system.


1. Orientation
i. Kineses: It is a behaviour in which an organism changes the speed Of random movements which help them to survive in the environment e.g., this type of behaviour enables pill bugs to reach the moist area which is required for their life:
ii. Pillbug or woodlouse: Any of numerous small land-dwelling crustaceans that in clammy woody places and are competent of rolling into a ball. Genera: Porcellio Also called sow bug.
iii. Taxis: In contrast to kineses a, taxis are a directed movement either towards (positive taxis) or away from (negative taxis) a stimulus.

2. Reflexes and instincts
These are extremely complex and include biological rhythms territorial behaviour, courtship (behaviour of male animals to attract females), (mating of animals or birds) ‘come together for breeding), aggression (attacking without any reason), altruism (concern for the needs and feelings of other people, above one’s: own), social hierarchies and social organizations.


Darwin (1859) was the first to propose an objective definition of instincts in terms of animal behaviour. He treated instincts as complex reflexes made up of units compatible ‘with the mechanisms of inheritance, and thus a product of natural selection, that had evolved together with the other aspects of life.
Explanation: The instinctive behaviour is a part of one’s inherited structure ‘by which the individual responses to a particular stimulus. This response is similar to members of a species. For example, all animals inherit certain responses which equip them to live having abilities like walking, moving running and eating, etc.
Sign stimuli: The early ethologists those who study animal behavior. e.g. Uexkull 1934, Lorenz 1935) thought that animals sometimes respond instinctively to specific though often complex stimuli, Such stimuli came to be called ‘sign stimuli”. A sign stimulus is a part of stimulus configuration and may be a relatively simple part. For example, a male three-spined stickle back fish has a distinguishing red belly when in breeding condition. This is a sign stimulus that elicits violent behavior in other territorial males.
Equip with series responses: Instinct will equipments an animal with series of responses this can be necessary for animals with short life spans and with very little or no parental care, as an example, a feminine sphecoid prepares a nest, catches caterpillars, kills them by sting puts them in the nest, lays eggs on them and so closes the nest. when doing all this, she dies. The larvae when rising from the eggs begin feeding on caterpillars killed by their mother before death and grow to digger wasps. All this can be completed among few weeks and is completed by instincts of sphenoid, which can be responding to the perception of a caterpillar (the potential sign stimulus) in a number of different ways.