Conflicts are ubiquitous in living world. Origin and resolution of many subtle and complex conflicts found especially in social animals are difficult to understand. Conflicts are many kinds, and may occur between prey and predators, between parasites and their hosts and even between members of same species competing for limited resources.
Evolution by natural selection is based on competition and survival of the fittest. Existence of these kinds of conflicts is not surprising. Conflict, even prolonged conflict is natural state in wild animals for much of their lives.
Sometimes decisions are taken at once, for example, escaping from an approaching predator. In many occasions, animals wait and collect more information before a decision is made. This is particularly useful in social situations, where animals take considerable time to ‘assess’ each other. Red deer stags take half an hour or more to assess each other’s fighting ability before deciding whether to attack or flee.
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Roaring matches and parallel walking are used by stags as indicators of likely outcome of a real fight and mean that animals remain in a state of continuous motivational conflict, while they gather relevant information.
Even escape from predation may be preceded by a period of lengthy assessment. Predator will attack them against loss of feeding time they would incur by moving away. Zebras watch hyaenas carefully and may flee realizing small differences in hyaenas’ behavior and size of hunting group.
Such assessments are highly adaptive but take time to make. Motivational conflict is resolved only when new information received tips the balance of causal factors in direction of one behavior or another.
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Second reason for prolonged motivational conflict, or remaining in a state of high motivation for a considerable length of time, is that it is for some reasons prevented from carrying out the behavior that it has ‘decided’ to do.
An animal may be stimulated to drink and all set to give top priority to dinking behavior over anything else, only to find that its water is covered with an immovable glass lid. Such an animal is called thwarted.
Alternatively, animals may be highly motivated to drink but unable to find any water at all. Such an animal is called frustrated. Both thwarting and frustration are commonly, but not exclusively seen where animals are kept in unnatural condition.
Understanding what happens when an animal remains highly motivated for long periods of time is critical in study of animal welfare and to understand the suffering and stress in animals. Animal exhibit symptoms of stress when kept in unnatural environments as distortions of decision- making mechanism (vide Manning and Dawkins, 2002).
Displacement Activities:
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Kortlandt (1940) and Tinbergen (1951) described a behavior typically observed in conflict situation called displacement activities. Common characteristic of such activities was their apparent irrelevance to situation.
In middle of a fight, two cockerels would turn aside briefly and peck at the ground, sometimes picking up stones or grains and allow them to fall again. Fighting gulls exhibit “grass is pulling” in middle of a fight.
A male stickleback courting an unreceptive female would suddenly swim to his nest and perform characteristic parental “fanning” movements, which ventilate nest with fresh water even though, there are no eggs.
An incubating tern in its nest makes preening movements just before it takes off at approach of an intruder. A thirsty dove is prevented from getting to its water bowl by a sheet of glass, may preen itself.
In these examples, animals are either thwarted or in a conflict between two opposing motivations. Feeding in middle of a fight in cockerels is surprising as it seems irrelevant to conflict.
When a tern is faced with situation of whether to escape from a predator or stay and incubate its eggs, preening seems irrelevant, irrelevant behavior is likely to occur, when animals remain in prolonged conflict and could not take decision.
Rowell (1961) performed experiment on Chaffinches by flashing a light, when they appraised their food dish. Birds were hungry but avoided light and were in a conflict between whether to feed or to escape.
There were several different perches in birds’ aviaries, so that they could either get as far away as possible form light by using most distant perch or approach, food dish by using nearest perch. Chaffinches did most displacement preening and bill- wiping on intermediate perches. Displacement activities mostly occur at a balance point between two conflicting tendencies but it is not conclusive.
Since birds paused for longer on intermediate perches, same result would be obtained, if preening simply occurred at a fairly constant rate.
Wherever a bird made a pause and was doing nothing else longer the pause, the more preening. Exact causal basis for displacement activities is still controversial (Roper 1984).
Displacement activities may not be such an unusual category as was once thought. If they occur in conflict situations and enable animals to gather a bit more information about their opponent or a potential predator that may be described as irrelevant but may not be irrelevant at all to the animals involved.
Conflict and Displays:
Many other displays seen as arising from unresolved motivational conflicts were initially called threats. However, present-day workers emphasize information about sender that a signal conveys (status, fighting ability etc) rather than its threatening or intimidating qualities. Tinbergen (1952) observed many signals resulting from dual motivation, conflict between simultaneously aroused tendencies to attack and escape, when neither can find separate expression.
Threat often occurred at boundaries between territories, where both tendencies to fight and to flee are aroused simultaneously. This might be called evidence from situation or context. Linked with this conclusion, mechanism of threat, which comes from independent manipulation of levels of attack and escape tendencies is also evident.
Blurton-Jones (1959) had a group of completely tame Canada geese which ignored him, if he was dressed in familiar old clothes. If he wore a white coat, geese attacked him uninhibitedly, whilst if he appeared carrying a broom they would flee.
Familiar threat postures of goose appeared only, when Blurton- Jones combined wearing a white coat with carrying a broom. Tinbergen (1959) gave a detailed analysis of threat postures of lesser black- backed gull. Bird moves towards its rival with neck stretched upward and slightly forward, and head and bill turned down. Wrist joints of wings are lifted clear of body and plumage is slightly raised.
Now, gulls normally launch an attack by beating with wings and attempting to peck down at their opponent. Rising of wings and down pointing bill look like actual attack. Elements of escape can be seen as two rivals come very close. Now, head moves increasingly back, bill becomes lifted and plumage sleeker.
Bird may turn sideways to its opponent and more parallel, not towards it. This turning aside looks like elements of escape. Gulf drawn back their heads and sleek plumage preparatory to taking not all threat postures can be interpreted as mixtures of attack and escape. Animals may use quite different displays as only “honest way” of signaling their fighting ability, rank and so on.
The idea of developing a model of fighting behavior of desert spider, Aegelopsis, is interesting. This spider is very aggressive and fights over access to web sites. In this model there are two variables, fear and aggression, which fluctuate during course of an encounter between two spiders.
Ownership of disputed web site depends relative body weight of two, territory quality and so on. Due to some genetic factors involved for it is known that some spider populations are more aggressive than others, even when external situation is kept constant.
On this model, if fear greatly exceeds aggression, animals simply withdraw. If fear is equal to or less than aggression, then contest continues but what behaviour is performed (locate -signal -threat-contact) depends on absolute levels of two variables.
This model with two variables is simplest one that will account for all observed data. Traditional idea of agonistic encounters as extended conflict has stood test of time although, there has perhaps been a shift of emphasis. Animals may display when they are in a state of conflict, not necessarily to signal that they are in a conflict, but by displaying and seeing displays of others, to get themselves out of conflict.
They make their decision on whether to attack or to flee from a rival or even a predator on the basis of new information received during course of encounter. Their decision to perform one or other behavior is then made in an adaptive way that would not have been possible without the period of extended conflict and exchange of information it made possible (Manning and Dawkin, 2002).