Animal Behaviour
by Mizanur Rahman Bhuiyan · January 6, 2014
Behaviour is a fundamental characteristic of animals, who survive and adapt to their surroundings only by the dint of it through their interactive expressions for their basic requirements and competetions. As blessed with locomotive power, the animals use their behavioural power for various purposes of their life, like – procuring food, selecting mates and mating with them for their descendants. So, behavioural changes in animals has been a way of their life since their origin and adaptive radiation. It is obvious, some of those changes are common to all for their survival and adaptation, but there are many which are very specific and vary animal to aninal. The study of animal behaviour has been so important to us at present that we can not think of an animal without studying its behaviour. Even the human race itself is not out of it, from the cave-man to the modern one, whom we can study properly through their behaviour. It becomes clear from the vivid Cave-arts engraved 4000 years ago that, humans alway wanted to convey some message to their descendents in any of their behavioural patterns. The term Ethology (ethos=character, habit, custom; logia=the study) has recently been coined, that pertains to a modern science dealing with animal behaviour. It was first coined by St. Hilaire in the last part of 18th century, ment as a science of habits and characteristics of animals, either instinct or acquired and their lerning capabilities or behavioural patterns; which vary time to time at different situations. So, Ethology has been defined as the study of behaviour within a zoological context and includes, Ecology, Genetics, Physiology and Psychology as well. We are indebted to Karl von Frish, Konrad Lorenz and Niko Tinbergen for developing such a section of Zoology in the very recent times, for which they were awarded the Nobel Prize in 1973 in the field of Physiology and Medicine.
By the term Behaviour, we mean the expressions of animal life for different aspects, like how it responds to its external (overt) and internal (covert) stimuli, how it learns to respond to those, how it procures its food, how it builds its house or nest, how it ensures its security, how it responds to its sexual attitude and convinces others to respond to it, and after all, how it defends its competents for food, shelter and sexuality. Definition of Behaviour In a word, all the activities done (seen or unseen) by an animal is its behavour which can be physical or psychological or psycho-physical and is either exposing or learning.
The Macaque monkeys of the Pacific Islands of Koshima of Japan, alike humans, washes the sweet potato with water before eating. This habit was not found in them earlier, but once a mother monkey learnt it from a human child while doing it. Gradually, the total population acquired this behaviour which they still exhibit. The Rainbow Lorikeet females comb the eye-plumages of males with their beautiful beaks, the Starlings (Mynas) clean their nest with neat skills, the Mongooses capture and dominate over their preys (Snakes) with much speed and clevery, and the Cheetahs approach their prey with extreem cover, care and silence – all those are their behavioural skills, according to scientiests, of which some are innate and others learnt; and the science dealing with those is Ethology. But, behaviour is not only upto this; like – the running of a prey for saving own life, running of a predator to capture a prey for own survival, wounderful archetechture of birds in building their nests and in spiders configuring their web, building under water entrance in a Beaver’s nest, incubating eggs and post-natal parental care, inter-continental migration of large and small birds in the same route and to a particular recurrent destination, non-stop day and night journey of migratory animals to a particular direction and location, etc. hundreds and thousands of activities are jointly known as animal behaviour. To adapt to the ever changing environment and at the same time to respond to different stimuli, an animal has to bring considerable change in its behaviour. This simulation continues for years, ultimately making the animal conditioned to it and which can even be genetically transmitted over generations. The external environment stimulates the nervous, endocrinal or muscular system of the animal, and as a reflex, the animal exhibits some other behaviour to respond to those, like – oral sound, physiclal movement, colour change (camouflage), emission of gas or smell, aggresive or frightened attetude etc.
A Stimulus is a signal, which can be identified and represents a sense. It can be both external and internal. For instance, when our cell phone rings, we can understand both by its tone and vibration, hence is a case of external stimulus. Likewise, when we get hungry, there is a different sensation that indulges us to take some food, so it is an internal stimulus. Obviously, the response to a cell phone is to respond to the call, while the response to a hunger is to take some food. The external stimuli involves – light, temperature, smell or aroma, a sound or a noise etc., while the internal ones are – love, hatrad, thirst, hunger, feelings etc. It is noteworthy, all animals do not necessarily have the same type of feelings and of a same level – rather it varies species to species. Human beings have – vision, audition, taste, smell and touch, these five types of stimuli which are always active, but it is never the case with other animals. Similarly, the gravitational and other magnetic forces have a great impact on birds and some other migratory animals, while those have no impact on us. Behavioural Changes due to Stimulus All our mental or behavioural conditions are stimulus based, which brings about responses. In this case stimulus-response law are applicable; the modernized form of which is stimulus-orgnism-response law. Further, these three elements combine to represent an Emotion. To behaviourists, emotion is never a mental contion but a physical change. Its a physiological, external or behavioural change. According to them, a change in environment can bring about emotional changes which changes the behaviour. So, the environment is the factor of behaviour and not the heredity – they believe. A Stimulus in an animal body creates emotion and different stimuli can create different emotions. The basic emotions in humans are – Happiness (Pleasure), Surprise (Quarry), Sadness (Sorrow), Anger (Temper), Disgustion (Hatrad), Fear (Shudder) etc. (Matsumoto & Ekman, 1989)
The following physiological changes takes place, due to any of the above emotions –
Behaviour is deeply related to heredity. The process through which paternal or maternal characteristics are transmitted to their offsprings, is known a heredity, due to which the latter resemble their parents. But, sometimes in some species variations are also seen and to understand all those resemblence and variance a branch of biological science, Genetics is underway for its knowledge and research. In other words, Genetics is the science of Gene and its functions and Genes are hereditary units, present in Chromosomal DNA and is responsible for carrying and transmitting single characters from parents to offsprings and in this way generation to generation. It is the peternal or metarnal genes which controls – the height and structure, complextion, colour of hair and iris etc. and even the mental conditon of a child, who receive it through pairs of genes, one from father and the other from mother. In case of animal behaviour, natural selection and genetics are involved; in fact, the role of genetics is important in case of animal behaviour. Particular genes for behaviour are selected naturally and become dominant in offsprings; that’s why the behaviourists use genetics in analysing the behavioural variations and accept genetical ideas in the following cases – So, determining the inherited pathway of behaviour is tough to identify, as so many genes interact among themselves as well as with environment, and along with that, genetics and environment influence each other. But, we are indebted to Gregor Johan Mendel, who has postulated two laws of genetics, the first law or the law of Seggregation and the second law or the law of Independant assortment. According to Mendel’s first law, a pair of genes (paternal and metarnal) having contrusting characteristics, is responsible for a given characteristic in an offspring, which never lose their integrity and seggegate out into two different gametes during its gametogenesis. Fig. 12.2 shows an example in this favour. The honey bees are attacked by a bacterial disease, American foulbrood (Bacillus larvae) resulting in the death of a number of bee larvae. So, the bees expell the infested larvae to reduce the probable attack and intensity of infestation. W. C. Rothenbuhler observed and identified two types of behaviour in them. There are one type of bees, called Hygenic, which can – Now, if a recessive gene ‘u’ is functional for uncapping the lids; and another recessive gene ‘r’ is functional for clearing the infested larvae; and, if a cross is made between a Hygenic bee (u/u, r/r) and a non-hygenic bee (U/O, R/O), then all the honey bees in the first filial generation will be non-hygenic. Only the worker bees (homozygous dominent) show normal behaviour. This is an example of genetical base of a given behaviour. Besides, the science of genetics is now used to show the influence of heredity upon behaviours related to – variations, environment and inherited characters:
Animal behaviour can be divided into two categories, like – a. Innate Behaviour and b. Learned Behaviour. The instinctive behaviour is sometimes called Innate, as it is inborn and need no learning. But there is no shart demarkation in between the two and in developed animals most of their behaviours is an overlaping of both. As for instance, we can consider the speech of a human. One can think its innate as all of us talk; but in fact, everybody can not speak. A born deaf, through tedious endeavour, can be taught how to speak; otherwise as a deaf is usually a dumb. In general we learn to talk listenning to others. That’s why our children talk in Bengali and a French child speach French. In fact, the power of speech in human is inherited, but what we speak, is learned.
The behavioural patterns in animals are the following –
A taxis or tactic movement is a type of movement of a freely motile organism, or a freely motile part of an organism, in response to a directional stimulus. Taxis is observed in plants and animals as well, and depends upon the nature of the stimulus. If the stimulus is such that the response draws the animal or plant closer to the source of stimulus, it is termed as Positive Taxis, and while it pushes plant or animal away from the source, it is termed as Negative Taxis. Taxis can vary from animal to animal and from plant to plant, and even from one part of the plant or animal body to the other. The best example of taxis is the growth of plant root and stem. We know, the former shows negative phototaxis, while the latter show positive phototaxis. Salient features of Taxis Kinds of Taxis Based upon the type of stimulus, taxis can be divided into the following categories –
The term Reflex was first coined by Sherrinton and can be defined as a simple act of behaviour in which an external or internal stimulus produces a specific, short-lived response. Reflex means the instant response produced due to a particular stimulus. It is controled by the Spinal cord and not by the Brain. So, the sequence in a reflex action is – Receptor (Epithelium) – Sensory neuron (Cell body) – Dorsal root (Spinal cord) – Synapse – Grey matter (Spinal cord) – Synapse – Motor neuron (Cell body) – Ventral root (Spinal cord) – Effector (Muscle). In this way, it is an instant response of a living body to an external or internal stimulus, induced through our epithelial tissue (touch or pressure) and responded by our muscular movements. For instance, any minute object falls in our eye, closes it or any small food particle stuck in our trachea or oesophagus induces choking. The parthway of a Reflex action (given above) is known as the Reflex Arc and one have no control over this action, as it is autonomous. Usually the Reflex actions are divided into two categories – Innate Reflex actions can be divided into two categories based on the position of receptors – The Salient features of Reflex behaviour are –
Instincts are innate natural behabiour that an organism exhibits in response to adapt to a change in the environment. “They are complex, inborn, stereotyped behavioural patterns of immediate adaptive survival value to the organism and are produced in response to sudden change in the environment”. They are unique for a given Species, differ from Species to Species and vary in their complexity from simple reflex to more complex one. Nobel loreate Conrad Lorenz explains instincts as – unlearned specific motor patterns of a given Species due to its biological rhythms, territorial behaviour, courtship and mating, social hierarchies including altruism. In some the behaviour is hereditary, like – in migratory birds, who become impatient for flying during the time of migration, even in captive condition; and when left alone, can find out its regular route of migration and a particular recurrent destination.
Adaptation is the capability or changes of an organism to synchronize with its ever changing environment. All Flora and Fauna exhibit the quality to adapt to their surroundings; and in animals their innate and learnt behaviours help them to do it.
Migration (Lat. migratus=wonder) is the movement of organisms temporarily or permanently from one place to other due to certain environmental causes. Migration in different birds is their instinct behaviour performed over years from generation to generation in quest of food, reproduction or cosy atmosphere which is more tolerant to them over a given period of a year. Migration can be local or continental, depending upon the need and situation as well as the body weight of the bird. Many of the bird from the northern hemishpere migrate throusands of miles to go to their esteemed destination of better food, shelter and spawnning ground in the southern hemisphere in the same route they perform it every year and at the same location they had come the previous years. Sometimes the latter is changed in quest of a better survival and spawnning but this is an uncommon phenomenon. Usually the tropical locations in the southern hemisphere is more feasible than that in the much colder northern one, their original habitat. So, migration can also be termed as a temporary change in habitat and habits. But, the southern hemisphere birds are found to be locally migrants and never a continental one to the northern. Birds which undergo migration are known a Migratory birds, who get back to their original habitat after the tough time has been over. Migration is an innate behaviour in certain birds and a common example is the winter bird migration to our country. Birds like – Bar-headed Goose (Anser indicus), Pintail (Anas acuta), Baikal teal (Anas formosa), Ruddy Shelduck (Tadorna ferruginea), Shrikes (Lanius sp.), Wagtails (Motacilla sp.), Leaf Warblers (Phylloscopus sp.), Finches (Pyrrhula sp.), Skylarks (Aluda sp.), Swallows (Hirundo sp.) etc. are examples of winter migrants in our country. Besides, Lesser and Greater Whistling teals (Dendrocygna sp.), Eagles (Haliaetus sp.), Pariah Kites (Milvus sp.), White backed Vulture (Gyps sp.), Hawks (Aviceda sp.), Malcoha (Rhopodytes sp.), few Owls (Strix sp.) etc. are locally migrants. The esturine and inland waters as well as the islands and marshy areas are traversed by – Gulls (Larus sp.), Terns (Sterna sp.), Spoonbill (Platalea sp.), Ibises (Plegadis sp.), Openbill (Anastomus sp.) and Adjutant (Leptopilos sp.) Storks, Sarus Crane (Grus antigone) etc. which are large locally migrant birds. So, this innate migratory behaviour of birds have been observes, tracked and experimented since a long time and today through satelite. It has been found that their navigation is either controlled by solar position by the day or star positions by the night or they have some other GPS positioning system within their brane still unknown to us. Anyway, the behaviour is peculiar and found to be trasmitted generation to generation. Same is observed in Green and other marine turtles who traverse a long way underwater for laying eggs in the same place they do every year during a particular period. So, the Stimuli or factors are directly involved with it are –
The Spider is a surprising animal and more peculiar is its web. Scientists believe this primitive animal has been existing since the Cretaceous era. The web is actually a secretion of a Spinneret gland present in its abdominal region and the web is prepared through its innate instinct. Biochemical experiments reveals that the web consists of combination of amino acids like – Glycine, Alanine, Serene and Tyrocine. The web is used for various purposes and the most significant and common one is capturing its prey through the web. Web Spinning Scientists believe that, during its change from the aquatic to terrestrial habitat in Devonian Era, the spider wrapped its body with a protective silky device, the web. Later, with considerable change in its constituents and conplicacy in weaving, the web has been an wounderful device today for both housing and food capture. The fibre used in it, just like in silk moth larva, is a secretion of their abdominal Spinneret gland, secreting 8 types of fibre today, each used for a different purpose. Some of those are used in climbing, others in housing, food capture, wrapping a prey and much more. Spiders are only animals in the world which captures their prey without minimum loss of energy; and that is possible by the dint of the web. But, it is noteworthy, a lot of time, energy and endeavour is spent by a Spider in building and maintaining its web through proteins out of its body. Moreover, the fibres lose their temper withing a short time when they have to rebuilt it losing more energy. The fibres are durable like Nylon, but more elastic; and at the same time they are stronger than steel fibres of the same diameter. From the weight bearing point of view they are next to fused Quartz fibres. The web maintains a lot of diagrametic archetechtural designs, that varies from species to species, but same for a given one. They can be sperical or ovoid, octagonal or multigonal, funnel shaped, spiral or tube shaped. But, whatever is its size the arrangement of fibre is very much even and scientific. The web is always attached to more than one substratum with equal strain at all sides. Usually the size depends upon the spider which is seen sitting at the centre or it hides building different structures on the web. Flying insects all over the world and even small birds in Amazon velly (taken by Brazilian large spiders) are confused by the web and never feel conscious about it. The fibre is liberated from the gland as liquid, made up of amino acids like – Glycine, Alanine, Serene and Tyrocine, which over its exposure to air and strain changes into a sticky fibre with much strain. The spider fixes the fibre at different points and move in a particular direction keeping even spaces among the central and circular weaving attachments in a web. The claws in its eight legs and unsmooth bristles around help them in weaving the net as well as walking at ease on any surface or in jumping. Sometimes it hangs for a long distance to understand the air flow and in quest of a suitable place for its web. Spiders are very intelligent creatures and keen listeners which can receive a vibration upto 1 GHz. Some of them build their web very quickly on the path of a flying insect, listenning to it buzzing and measuring its speed, weight and direction. It understands its success by the vibration produced in the net, when it comes forward and very quickly wrappes its prey with huge fibre. When the prey has almost lost its energy, the spider poisions it and takes time in sucking its body materials gradually.
Parental care in fishes is rare but very distinctive in some. Each of the functions related to offspring like – Egg laying, Preparing a nest and securing it for egg laying, raring of newly spawned fries for a definite period, all fall under parental care. In fishes, the male or female or both take part of share in the practice. The male Sun fish prepares a cup-like nest for the egg laying purpose of the female. Lung fishes like Protopterus and Lepidosiren make out deep holes where the female lays their eggs. During the spawnning the male guards the nest. Likewise, Amia prepares a circular nest with acquatic plants. The male Three-spine Stickleback (Gasterosteus aculeatus) selects a place and prepares a nest with plant parts and roots, mixing sticky materials secreted from their kidneys. The nest has a central tunnel where the female lays its eggs and the male fertilizes them later. Then they stand at one side of the tunnel and fan with their Pectoral fins so that a water current is produced through the tunnel increasing the Oxygen content of the water in it. In this way they wail till the eggs are hatched and again they guide the fries for the next 15 days till they become able to move in shoals. Besides, Tilapia (Tilapia mossabica) is a mouth breeder, i.e., the fertilized eggs are housed in the buccal cavity and released later. The male Sea Horse (Hippocampus sp.) carry fertilized eggs and care them till hatching.
The parental care in Amphibians like – Toad or Frog is very rare and not more than 20%. But, they adopt innate techniques, for egg laying, protecting, proper hatching and protecting the young ones. Frogs’ (e.g., Toad-like Frog Alytes) tendency for parental care depends upon their habitats especially the area of water body they spawn in. Usually the intensity and variation of parental care increases with smaller water bodies. As the probability of attack from a predator is higher in a larger water body, the amphibians adopt a number of preventive measures to protect their young ones. Sometimes it is observed that they lay eggs on the shores and regularly keep them moist for a better hatching and then transfer the hatched ones into the water. Parents take part in all those events. All their events can be summerized in the following points – In this way, Amphibians exhibit wounderful parental care from their egg laying stage till the growth of larvae into adult stage.
The parental care in Aves, i.e., birds is very distinctive feature in them. We observe a kind of helplessness to self-reliance attitude in their life. Many of the altrician birdlings are smaller in size, sight and featherless, devoid of movement, seriously helpless and depended on parental care and nestling. But, on the other hand many precocian birdlings can move, are feathered and collect their own food i.e., are selfdependant. So, the former type needs parental care over a longer period of time while the latter needs it for a very short period. The stages of parental care in birds are as follows –
The behaviour which is acquired and modified in response to experience is called learned behaviour. For instance, a birdling of 3 days learns how to peak at food and Honey bees learn to identify flowers with more necter. The main benificial feature that works inharently in learning behaviour is adaptability, in comparison to innate behaviour. So, it can be changed keeping pace with the surrounding requirements or changes. In one word, a learning behaviour is the achievement of a new behavioural pattern, based upon previous experience. W. H. Thorpe (1963) has defined learning as – “That processes which manifests itself by adaptive changes in individual behaviour as a result of experience“. Lorenz (1969) defined learning as – “An adaptive change in behaviour that results from experience“.
There is no acceptable or unanymous classification of Learning yet. But, it can be categorized as follows – It is the simplest learning behaviour. In this case due to the continued lack of prize or punishment the animal gradually turns nonresponding to a given stimulus. So, it rather can be termed as a learning not to respond to a given stimulus. The merits of habituation includes responding to a peculiar stimulus with a probability of danger and subsequently not responding to it feeling safe due to the lack of any consequense of it. Habituation is a common learning behaviour, observed everywhere in the animal world. For instance, when touched even by a leaf, a snail retreats back into its shell. It continues doing this over and over as touched more and more. But, after a few retructions, it avoids the stimulus being habituated not receiving any harm from it; it continues its movement without responding to the stimulus. Another instance is the fledding of Pegions from crop field with a Gunshot bird-scaring device. The birds respond to it in the primary sequences but not later, as they observe it over a period of time that there is no reaction or consequense of those noises. Later instead of the noise, they continue their feeding peacefully in the cropfield without flying away, what they did in the beginning, a few times. Likewise, we can easily sleep inside a loud but familiar noise, but on the other hand we wake up in a small sound, which is new or peculiar to us. Associative learning includes the involvement of two or more Stimuli at a time. In this process an animal can identify a Stimulus and can understand what is going to happen along with it; as it knows the situation which happened multiple times earlier. In this case the animal involves two Stimuli together. For instance, the going of a Farmar to his cropland by a Tractor is reacted by his Cattles, but doing such on other veheicles are overlooked. Because, the Cattle involves the Tractor and the Farmar with their food. Conditioning is of two types – A. Classical or Pavlovian Contioning and B. Operant Conditioning (Trial and Error Learning) In 1902 a Russian Physiologist, Ivan P. Pavlov (1849 – 1936) studied the secretion of saliva in Dog due to food reaction. He observed, the vision, smell and the taste of food induces or changes the section of saliva. His experiment (Fig. 12.3) was as follows – So, in this experiment, the Dog learns the involvement (relationship) of sound with food. This type of learning is termed as Classsical Conditioning. The response of saliva secretion with the ring of bell is a case of Conditioned Reflex. It is obvious that, the presentation of food is necessary within 1:00 minute of the sound production, to trigger the condioned reflex. Features of Conditioned Reflex Imprinting is a kind of simple but specialized learning. In comparison to others the Imprinted behaviour is fixed and not easily adapted. During the early days of their life cycles, Birds and Mammals undergo imprinting specially in their Receptive Stage (Critical period – Lorenz; Sensitive period – Recent). At this period the newly born individuals develop a bond with a comparatively large moving object and develop their permanent relationship on the basis of physical contact or heat reception. For example, a newly hatched goose follows anything moving infront of it. Naturally, mother is their first target of movement they try to follow. But, Australian zoologist and founder of Ethology, Conrad Lorenz, in his renowned book – King Solomon’s Ring describes that, parentless gooselings and ducklings followed him and considered him as their alternative parent. He revealed and described a wounderful practical instance of imprinting in Greyleg Goose (Anser anser) (Fig. 12.4) In nature there are examples exposing adaptive significance, like – the learning capability through parents; e.g., learning how to fly, capture a prey, fight a foe or run away from a predator. For instance, the `smell’ of the steam in which migratory Salmon were hatched and to which they return to spawn.
The term Altruism (Fr. altruisme, Ital. altrui) is a philosophical theory, postulated by welknown French Philosopher August Kooth. The term means –
- Unselfish regard for or devotion to the welfare of others.
- Behaviour by an animal that is not beneficial to or harmful to itself but that benefits others of its species.
According to this theory, each and every individual has its own generic characteristics which increases peace and happiness and decreases sorrow or unhappiness in others. One thing has to be found in this context, whether peace or happiness is the real target of life. The answer is, the real peace lies under the happiness of others, i.e., peace is achieved only when someone does some selfless dedication for his mates.
Altruistic Behaviour in Honey Bee Hive
The Honey bee (Apis) is a social insect and maintains a peculier life style. They live a colonial life in a bee hive, containing about 60,000 – 70,000 members, maintaing an organized systematic order of life with a division of labour for each and every individual. There are three castes found in a hive – The Queen, Drones and Workers.
The queen is the only fertile female in the colony, easily identified for its very large size and shape, who lays about 1000 – 1500 eggs per day; eggs can be fertilized and unfertilized. Within a week of its birth, the queen can mate a Drone and starts laying eggs within the next 2-3 days. She survives for 2-3 years and continuously enriching its colony. Form her fertilized eggs are produced the Workers, huge in number and from the unfertilized ones the Drones, few in number.
The Drone is bigger than a worker but smaller than the queen, healthy in structure and doing only a single function – mating the queen and survive a period of 2-12 days. According to some, they die just after the copulation and are taken up by other members (canabalism).
The workers are unfertile females, unable to produce eggs. But, some can give unfertilized eggs in absence of a queen from which small unfertile males generate. These female worker bees are called egg laying workers and can produce at best 28 eggs in their total life. The workers perform almost all the duties in a colony other than fertilizing an egg or mating, like –
- They consturct the bee hive with their body wax and ensure the security of the total colony.
- They forage a long distance in quest of honey and flower and bring information to the colony.
- They lead the total workers’ team to the esteemed target flowers and collect honey as a team-work.
- They scoop up the necter from the nectries of flowers and keep it for a time being in their very large crop where they let the necter to mix with their enzymes and which then converts into honey.
- They then pour the honey in a given pocket of the bee hive and fan it for dehydration.
- They rare the eggs keeping them in special cells in the hive, take care of larvae as they come out of eggs by feeding them Royal Jelly, a paste prepared with honey and their salivary juice; some larvae are fed with bee-bread, a mixture of pollen and honey.
- The royal jelly fed larvae turn into workers and drones, while the bee-bread eaters turn into queens.
- After a few ecdysis (moulting) the larvae convert into adult bees, but the interim guidance is given by workers.
- In case that the colony members have attained their maximum limits, a new queen with a number of drones and a huge number of workers, start for a new destination, built a hive there and lead a next colony.
- Even in that case, the workers bring information and location of the new colony site and build a hive in there.
So, the social life of Honey bees, especially the workers, is the best example of Altruistic behaviour.
|date=, |accessdate=
(help)
Photo Credit: Capt. Kawsar Mostafa