Animal Behavior in Quest for Survival
Animal Aggression Over Resources
Aggression is utilized by several animals to get access to resources like food. A primary delight of researchers on the African savannas is keeping track of which hyenas killed a wildebeest, which lions stole the carcass from them (or the other way around), and which jackals and vultures contended to snatch a bite before being driven away. Such engagement makes a dramatic spectacle. Most animals don't usually clash in this manner. The wildebeest being scrambled over did not, in life, present bloody battles with other wildebeest over which of them would graze a patch of grass.
Competition demands loads energy, and a lot of species appear to minimize such strife. In several animals there are attitudes of surrender that subdue the attacker of the same species. The monkey looks away, the wolf rolls on its back, and the attacker stops. What does an aggressor experience whose attack is arrested in this process? For numerous animals the creature likely to be its nearest competitor, to desire the same foods or the same nest sites, is another of its species, in some circumstances its own mate. Research points out that size variation within some species bestows survival advantage. For instance, a female osprey is bigger than her mate; they catch fish of different sizes, which brings down competition between them, increasing their collective supply of food.
Tame parrots often take a heavy dislike to individual humans or to classes of humans, a great deal to a whole gender. Veterinarians can become weary of hearing clients say, "He hates all men. He might have been abused by a man in the past." Parrots have been recognized to conceive hatreds of all brunettes, all redheads, or all adults. While all wild-caught parrots have been abused, because of the cruelty involved in their capture and transport, this is more improbable for parrots brought up in captivity. But it stays unidentified whether these kinds of bizarre dislikes are observed in the wild. Maybe these parrots merely enjoy having enemies. This might promote flock solidarity, avoid interbreeding between species, fortify the pair bond, or have some other useful function. Another hypothesis is that the temper of parrots is related to dominance scrambles in the flock.
Since it was announced in the 1920s that chickens have "pecking orders," ethologists have been looking for and finding pecking orders—now known as dominance hierarchies—everywhere. In a pecking order a chicken is dominant to another chicken, and can peck them and push them away from food—unless it's the lowest-ranking chicken of all. And, unless it's the top bird, other chickens may in turn be dominant to it, and the chicken will permit these birds to peck it and expel it from food. The idea of dominant and submissive animals has found wide public popularity. So has the idea that aggression is useful because it helps an animal dominate.
In later years the idea of the dominance hierarchy has become more controversial, with a few scientists asking if such hierarchies are real or a product of human outlook. It is worth noting that in wild flocks, chickens don't form rigid pecking orders as they do in poultry yards.
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