Топтың әлеуметтік ұйымдасуы және мал бағып күтушілер

Similar as Group

A herd is a social group of certain animals of the same species, either wild or domestic. The form of collective animal behavior associated with this is called herding. These animals are known as gregarious animals. The term herd is generally applied to mammals, and most particularly to the grazing ungulates that classically display this behaviour. Different terms are used for similar groupings in other species; in the case of birds, for example, the word is flocking, but flock may also be used for mammals, particularly sheep or goats. Large groups of carnivores are usually called packs, and in nature a herd is classically subject to predation from pack hunters. Special collective nouns may be used for particular taxa (for example a flock of geese, if not in flight, is sometimes called a gaggle) but for theoretical discussions of behavioural ecology, the generic term herd can be used for all such kinds of assemblage. The word herd, as a noun, can also refer to one who controls, possesses and has care for such groups of animals when they are domesticated. Examples of herds in this sense include shepherds (who tend to sheep), goatherds (who tend to goats), and cowherds (who tend to cattle).

When an association of animals (or, by extension, people) is described as a herd, the implication is that the group tends to act together (for example, all moving in the same direction at a given time), but that this does not occur as a result of planning or coordination. Rather, each individual is choosing behaviour in correspondence with most other members, possibly through imitation or possibly because all are responding to the same external circumstances. A herd can be contrasted with a coordinated group where individuals have distinct roles. Many human groupings, such as army detachments or sports teams, show such coordination and differentiation of roles, but so do some animal groupings such as those of eusocial insects, which are coordinated through pheromones and other forms of animal communication. A herd is, by definition, relatively unstructured. However, there may be two or a few animals which tend to be imitated by the bulk of the herd more than others. An animal in this role is called a "control animal", since its behaviour will predict that of the herd as a whole. It cannot be assumed, however, that the control animal is deliberately taking a leadership role; control animals are not necessarily socially dominant in conflict situations, though they often are. Group size is an important characteristic of the social environment of gregarious species.

The reason why animals form herds can not always be stated easily, since the underlying mechanisms are diverse and complex. Understanding the social behaviour of animals and the formation of groups has been a fundamental goal in the field of sociobiology and behavioural ecology. Theoretical framework is focused on the costs and benefits associated with living in groups in terms of the fitness of each individual compared to living solitarily. Living in groups evolved independently multiple times in various taxa and can only occur if its benefits outweigh the costs within an evolutionary timescale. Thus, animals form groups whenever this increases their fitness compared to living in solitary. The following includes an outline about some of the major effects determining the trade offs for living in groups.

Perhaps the most studied effect of herds is the so called dilution effect. The key argument is that the risk of being preyed upon for any particular individual is smaller within a larger group, strictly due to the fact that a predator has to decide which individual to attack. Although the dilution effect is influenced by so called selfish herding, it is primarily a direct effect of group size instead of the position within a herd. Greater group sizes result in higher visibility and detection rates for predators, but this relation is not directly proportional and saturates at some point, while the risk of being attacked for an individual is directly proportional to group size. Thus, the net effect for an individual in a group concerning its predation risk is beneficial. Whenever groups, such as shoals of fish, synchronize their movements, it becomes harder for predators to focus on particular individuals. However, animals that are weak and slower or on the periphery are preferred by predators, so that certain positions within the group are better than others (see selfish herd theory). For fit animals, being in a group with such vulnerable individuals may thus decrease the chance of being preyed upon even further. However, some details about this concepts remain unclear. Being the first to detect predators and react accordingly can be advantageous, implying individuals may not fully be able to rely only on the group. Moreover, the competition for food can lead to the misuse of warning calls, as was observed for great tits: If food is scarce or monopolized by dominant birds, other birds (mainly subordinates) use antipredatory warning calls to induce an interruption of feeding and gain access to resources. Another study concerning a flock of geese suggested that the benefits of lower vigilance concerned only those in central positions, due to the fact that the possibly more vulnerable individuals in the flock's periphery have a greater need to stay attentive. This implies that the decrease in overall vigilance arises simply because the geese on the edge of the flock comprise a smaller group when groups get large. Since foraging may be energetically costly (searching, hunting, handling, etc.) and may induce risk of predation, animals in groups may have an advantage, since their combined effort in locating and handling food will reduce time needed to forage sufficiently. Thus, animals in groups may have shorter searching and handling times as well as an increased chance of finding (or monopolizing) highly profitable food, which makes foraging in groups beneficial for time minimizers and energy maximizers alike. A similar effect can be observed when fish swim together in fixed formations. Another benefit of group living occurs when climate is harsh and cold: By staying close together animals experience better thermoregulation, because their overall surface to volume ratio is reduced. Consequently, maintaining adequate body temperatures becomes less energetically costly.

The collective force of a group mobbing predators can reduce risk of predation significantly. Flocks of raven are able to actively defend themselves against eagles and baboons collectively mob lions, which is impossible for individuals alone. This behaviour may be based on reciprocal altruism, meaning animals are more likely to help each other if their conspecifics did so earlier.

Animals living in groups are more likely to find mates than those living in solitary and are also able to compare potential partners in order to optimize genetic quality for their offspring.

Domestic animal herds are assembled by humans for practicality in raising them and controlling them. Their behaviour may be quite different from that of wild herds of the same or related species, since both their composition (in terms of the distribution of age and sex within the herd) and their history (in terms of when and how the individuals joined the herd) are likely to be very different.

The term herd is also applied metaphorically to human beings in social psychology, with the concept of herd behaviour. However both the term and concepts that underlie its use are controversial. The term has acquired a semi technical usage in behavioral finance to describe the largest group of market investors or market speculators who tend to "move with the market", or "follow the general market trend". This is at least a plausible example of genuine herding, though according to some researchers it results from rational decisions through processes such as information cascade and rational expectations. Other researchers, however, ascribe it to non rational process such as mimicry, fear and greed contagion. "Contrarians" or contrarian investors are those who deliberately choose to invest or speculate counter to the "herd".