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Boy herding a flock of sheep, India; a classic example of the domestic herding of animals
Wildebeest at the Ngorongoro Crater; an example of a herd in the wild

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 referred to as herding.




Reasons for animals to form a herdEdit

Large groupings of birds in flight are generally referred to as a flock

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 that corresponds to that of the majority of 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.

Traditional herding of goats in Greece. Overgrazing by poorly managed traditional herding is one of the primary causes of desertification and maquis degradation.
Wildebeest in Masai Mara during the Great Migration. Overgrazing is not caused by nomadic grazers in huge populations of travel herds,[1][2] nor by holistic planned grazing.[3]

The question of why animals group together is one of the most fundamental in sociobiology and behavioural ecology. As noted above, the term herd is most commonly used of grazing animals such as ungulates, and in these cases it is believed that the strongest selective pressure leading to herding rather than a solitary existence is protection against predators. There is clearly a tradeoff involved, since on the one hand a predator may hesitate to attack a large group of animals, while on the other a large group offers an easily detected target. In the case of predators, it is often unclear whether the term herd is appropriate, since there may be some degree of coordination or role differentiation in group hunting. Predator groups are commonly smaller than grazing groups, since although a pack may be more effective at pulling down prey than a single animal, the prey then has to be shared between all members, so that the weaker animals will often be better off hunting smaller prey on their own.

The structure and size of herdsEdit

A herd is by definition relatively unstructured. However, there may be two[4] or a few animals which tend to be imitated by the rest of the members of the herd more than others. An animal taking 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, or even usually, those that are socially dominant in conflict situations, though they frequently are. Group size is an important characteristic of the social environment of gregarious species.

A snow goose gaggle may contain thousands.

Domestic herdsEdit



Human parallelsEdit


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".

See alsoEdit


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