10 julio, 2024

Irritability in animals: what it is, characteristics, types and examples

What is irritability in animals?

The irritability in animals It is the ability to respond to physical and chemical changes in your internal and external environment. Thanks to it they can survive and defend themselves from those changes that they consider threatening and dangerous, and react.

Unlike unicellular organisms that generate simple responses, multicellular organisms such as animals have highly specialized receptor organs that receive stimuli and transmit them so that the organism generates the response.

The nervous system and the endocrine system are responsible for receiving stimuli and coordinating their respective response.

Irritability has a homeostatic purpose in the body, that is, to keep its internal conditions constant such as body temperature, the amount of circulating blood, the amount of oxygen that is received or the amount of water needed.

What distinguishes the irritability of living organisms from the reactions in inert beings is that the response of the latter will always be the same (a metal corrodes in the presence of an acid), while the reaction of a living being differs. .

Characteristics of irritability

– It is a physical or emotional response to an external stimulus.

– It can manifest itself in a variety of behaviors, such as growling, barking, biting or scratching.

– It can be a normal response to stressful or aversive situations, but it can also be a symptom of disease or trauma.

– The intensity and frequency of irritability varies between different species and between individuals.

– It can be controlled through training, proper handling and health care of the animal.

Complexity in the manifestations of irritability

Single-celled organisms, such as bacteria, manifest their irritability by changing the rate of cell division and moving away from or toward the stimulus. Their answers are not very varied or complex because they lack organic coordination and integration systems.

For their part, plants slowly move away from or approach the stimulus (tropism) thanks to their hormonal coordination and integration system called phytohormones.

Animals, on the other hand, are multicellular organisms and, consequently, have an endocrine and a nervous system that are made up of highly specialized organs, linked through a complex communication network that delivers a response in a matter of seconds.

Anything to which an organism responds or reacts is called a stimulus.

types of irritability

1. Tactisms

They are the innate, fixed and inevitable behaviors performed by lower animals such as invertebrates. They are fast, wide movements that move the individual to bring him closer to or away from the stimulus.

If the movement leads to an approach of the stimulus, it is called positive tactism. If the movement leads to a withdrawal from the stimulus, it is called negative tactism.

The most common agents of tactism are light, gravity, water, and touch.

2. Reflexes

They are involuntary, fast and pre-established animal responses of a part of the organism against certain stimuli.

Most of the cases are about movements, but it can also be exclusively or includes hormonal secretion.

In this case, the stimulus does not travel through the neurons until it reaches the brain (central nervous system), but rather the receptor will send it to the spinal cord, which will activate the motoneurons and these will produce muscle movement (muscle tension) or hormonal secretion, if the response is of an endocrine type. This happens in a matter of a fraction of a second.

Reflexes can be innate or acquired. Breathing, swallowing or blinking are innate or unconditioned reflexes that appear during or after birth and are carried out automatically without the participation of the brain.

Instead, acquired or conditioned reflexes are adopted over time through a learning process in which the brain participates, establishing a relationship between a stimulus and a reinforcement (like Pavlov’s dogs).

When an innate reflex to an acquired one is exercised, then it is strengthened, but if the stimulus is not exercised, it eventually weakens and eventually disappears.

3. Instincts

They are innate reactions, more complex and elaborate, in which various reflexes are involved. These are innate, fixed and specific behaviors that are genetically transmitted between individuals of the same species to respond in a certain way to certain stimuli.

Being a type of genetic animal irritability with adaptive purposes, in many cases they result from the evolutionary process of the species.

Vital instincts are present in all animals, while pleasure and social instincts are more common in more evolved species. The cultural ones are exclusive to the human being.

Examples of Irritability in Animals

– Pangolins roll up on themselves when they feel threatened.

– The expulsion of the “ink” from squids and octopuses to defend themselves from possible predators.

– The reaction of cats and dogs to the explosion of firecrackers: their hearts beat faster and they hide.

– When ostriches hide their heads in the sand, they are protecting themselves from some danger.

– The posture of cats when their backs are curved and their body hairs stand on end: it is a reaction of fear or alertness to a possible danger.


Irritability and Nervous System. Recovered from ssla.cl
Response and Coordination in Plants and Animals. Retrieved from biologydiscussion.com

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