247:
331:
209:
226:
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.
1016:
167:
319:
34:
462:
383:, animals always try to maximize their net energy gain when feeding, because this is positively correlated to their fitness. If their energy requirement is fixed and additional energy is not increasing fitness, they will use as little time for foraging as possible (time minimizers). If on the other hand time allocated to foraging is fixed, an animal's gain in fitness is related to the quantity and quality of resources it feeds on (Energy maximizers).
302:, 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.
185:
46:
390:, 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.
355:
vigilance arises simply because the geese on the edge of the flock comprise a smaller group when groups get large. A special case of collective vigilance in groups is that of sentinels. Individuals take turn in keeping guard, while all others participate in other activities. Thus, the strength of social bonds and trust within these groups have to be much higher than in the former cases.
372:
shown that larger groups of lions tend to be more successful in protecting prey from hyenas than smaller ones. Being able to communicate the location and type of food to other group members may increase the chance for each individual to find profitable food sources, a mechanism which is known to be used by both bees (via a
410:
diseases and parasites spread much easier between them compared to solitary animals. Studies have shown a positive correlation between herd size and intensity of infections, but the extent to which this sometimes drastic reduction in fitness governs group size and structure is still unclear. However,
397:
with other group members. In general, it is clear that the amount of resources available for each individual decreases with group size. If the resource availability is critical, competition within the group may get so intense, that animals no longer experience benefits from living in groups. However,
444:
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
354:
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
225:
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
350:
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
305:
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
297:
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
229:
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,
473:
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
371:
is able to corral fish into a smaller volume, which makes catching them easier, as there is less opportunity for the fish to escape. Furthermore, large groups are able to monopolize resources and defend them against solitary animals or smaller groups of the same or different species. It has been
346:
and animal decision making. While animals under the risk of predation are feeding or resting, they have to stay vigilant and watch for predators. It could be shown in many studies (especially for birds) that with increase in group size individual animals are less attentive, while the overall
431:
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.
427:
Staying together in groups often brings energetic advantages. Birds flying together in a flock use aerodynamic effects to reduce energetic costs, e.g. by positioning themselves in a V-shaped formation. A similar effect can be observed when fish swim together in fixed formations.
261:
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
505:
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
821:
Pyke, G. H., Pulliam, H. R., & Charnov, E. L. (1977). Pyke etal-1977. Optimal foraging-a selective review of theory and tests. the quarterly review of biology. In The
Quarternarly Review of Biology (Vol. 52, Issue 2, pp.
351:
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.
363:
Hunting together enables group-living predators, such as wolves and wild dogs, to catch large prey, which they are unable to achieve when hunting alone. Working together significantly improves
453:
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.
398:
only the relative importance of within- and between-group competition determines the optimal group size and ultimately the decision of each individual whether or not to stay in the group.
282:
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.
347:
vigilance suffers little (many eyes effect). This means food intake and other activities related to fitness are optimized in terms of time allocation when animals stay in groups.
151:, 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
752:
The role of passive defense (selfish herd and dilution effect) in the gregarious nesting of
Liostenogaster wasps (Vespidae, Hymenoptera, Stenogastrinae).
89:
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
1358:
367:
efficiency, meaning the net energy gain of each individual is increased when animals are feeding collectively. As an example, a group of
831:
Portugal, S. J., Hubel, T. Y., Fritz, J., Heese, S., Trobe, D., Voelkl, B., Hailes, S., Wilson, A. M., & Usherwood, J. R. (2014).
310:). For fit animals, being in a group with such vulnerable individuals may thus decrease the chance of being preyed upon even further.
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1227:
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658:
976:
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339:
246:
634:
230:
however, that the control animal is deliberately taking a leadership role; control animals are not necessarily
334:
Meerkats (Suricata suricatta) take turn to keep guard while other members of the group are resting or feeding.
270:. Theoretical framework is focused on the costs and benefits associated with living in groups in terms of the
937:
888:
561:
1184:
1137:
893:
132:
may be used for particular taxa (for example a flock of geese, if not in flight, is sometimes called a
69:
1071:
1042:
942:
880:
441:
474:
history (in terms of when and how the individuals joined the herd) are likely to be very different.
1384:
1222:
692:
1303:
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1323:
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Since foraging may be energetically costly (searching, hunting, handling, etc.) and may induce
20:
626:
1132:
1037:
511:
394:
27:
765:
Evidence for the dilution effect in the selfish herd from fish predation on a marine insect.
1343:
1308:
1146:
1093:
1000:
586:
523:
91:
599:
Krause, J., & Ruxton, G. D. (2002). Living in groups. Oxford: Oxford
University Press.
214:
Wildebeest in Masai Mara during the Great
Migration. Overgrazing is not caused by nomadic
198:
by poorly managed traditional herding is one of the primary causes of desertification and
8:
1353:
1328:
1318:
908:
551:
519:
507:
307:
299:
267:
235:
231:
1156:
741:. In J. Vonk & T. Shackelford (Eds.), Encyclopedia of Animal Cognition and Behavior.
1333:
1194:
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701:
494:
250:
330:
1379:
1298:
1217:
1204:
1164:
1005:
849:
806:
793:
630:
619:
571:
483:
271:
833:
Upwash exploitation and downwash avoidance by flap phasing in ibis formation flight.
208:
1389:
1179:
1127:
1110:
1032:
1024:
690:
David S. Scharfstein; Jeremy C. Stein (June 1990). "Herd
Behavior and Investment".
199:
160:
285:
The following includes an outline about some of the major effects determining the
995:
872:
794:
False Alarm Calls as a Means of
Resource Usurpation in the Great Tit Parus major.
416:
368:
129:
665:
526:
are those who deliberately choose to invest or speculate counter to the "herd".
376:) and several species of birds (using specific vocalisations to indicate food).
238:
is an important characteristic of the social environment of gregarious species.
1338:
1272:
1249:
1083:
1078:
1061:
1054:
947:
781:
Behavioral decisions made under the risk of predation: a review and prospectus.
487:
1015:
490:. However both the term and concepts that underlie its use are controversial.
1373:
1212:
954:
925:
903:
581:
576:
546:
113:
65:
738:
659:"Bison Conservation: Saving an Ecologically and Culturally Keystone Species"
1293:
1267:
1257:
1234:
1115:
373:
263:
166:
751:
318:
1313:
1262:
1103:
959:
514:. Other researchers, however, ascribe it to non-rational process such as
254:
195:
122:
33:
1120:
1098:
705:
502:
461:
393:
The obvious disadvantage of foraging in groups is (scramble or direct)
323:
49:
832:
406:
Since animals in groups stay near each other and interact frequently,
85:
is generally applied to mammals, and most particularly to the grazing
1348:
988:
466:
407:
286:
275:
118:
108:
1277:
1239:
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of each individual compared to living solitarily. Living in groups
156:
152:
86:
61:
780:
898:
541:
515:
342:
in social groups has been widely studied within the framework of
215:
137:
74:
60:
is a social group of certain animals of the same species, either
482:
The term herd is also applied metaphorically to human beings in
465:
A shepherd guiding his sheep through the high desert outside of
184:
932:
556:
45:
1174:
279:
100:
41:, India; a classic example of the domestic herding of animals
38:
750:
Coster-Longman, C., Landi, M., & Turillazzi, S. (2002).
841:
191:
104:
241:
52:
at the
Ngorongoro Crater; an example of a herd in the wild
807:
Vigilance and Flock Size in Brent Geese: The Edge Effect.
621:
All Our
Relations: Native Struggles for Land and Life
1359:Task allocation and partitioning of social insects
809:Zeitschrift Für Tierpsychologie, 57(3–4), 193–200.
618:
174:
136:) but for theoretical discussions of behavioural
117:, and in nature a herd is classically subject to
78:. These animals are known as gregarious animals.
1371:
493:The term has acquired a semi-technical usage in
411:some animals have found countermeasures such as
234:in conflict situations, though they often are.
650:
144:can be used for all such kinds of assemblage.
857:
763:Foster, W. A., & Treherne, J. E. (1981).
783:Canadian Journal of Zoology, 68(4), 619–640.
733:
731:
729:
727:
725:
723:
721:
719:
717:
715:
445:other if their conspecifics did so earlier.
19:"Covey" redirects here. For other uses, see
817:
815:
754:Journal of Insect Behavior, 15(3), 331–350.
99:may also be used for mammals, particularly
864:
850:
775:
773:
625:. Cambridge, MA: South End Press. p.
435:
805:Inglis, I. R., & Lazarus, J. (1981).
712:
401:
812:
497:to describe the largest group of market
460:
329:
317:
278:independently multiple times in various
245:
165:
44:
32:
779:Lima, S. L., & Dill, L. M. (1990).
770:
422:
313:
242:Costs and benefits of animals in groups
1372:
616:
967:Patterns of self-organization in ants
845:
737:Majolo, B., & Huang, P. (2020).
218:in huge populations of travel herds.
13:
977:symmetry breaking of escaping ants
477:
298:effect is influenced by so-called
292:
14:
1401:
664:. Duke University. Archived from
656:
456:
1014:
440:The collective force of a group
207:
183:
825:
253:created by a herd of cattle in
175:The structure and size of herds
72:associated with this is called
799:
786:
757:
744:
683:
610:
1:
603:
593:
326:gaggle may contain thousands.
938:Mixed-species foraging flock
889:Agent-based model in biology
871:
562:Catalina Island buffalo herd
7:
1185:Particle swarm optimization
835:Nature, 505(7483), 399–402.
767:Nature, 293(5832), 466–467.
529:
358:
170:A herd of cattle in Punjab.
10:
1406:
894:Collective animal behavior
70:collective animal behavior
25:
18:
1286:
1248:
1203:
1155:
1023:
1012:
879:
448:
338:The effect of collective
159:(who tend to goats), and
1223:Self-propelled particles
693:American Economic Review
1304:Collective intelligence
1170:Ant colony optimization
796:Ethology, 79(1), 25–30.
617:Laduke, Winona (1999).
436:Antipredatory behaviour
381:Optimal foraging theory
344:optimal foraging theory
190:Traditional herding of
37:Boy herding a flock of
1324:Microbial intelligence
984:Shoaling and schooling
792:Møller, A. P. (2010).
567:Shoaling and schooling
486:, with the concept of
470:
402:Diseases and parasites
335:
327:
289:for living in groups.
258:
171:
163:(who tend to cattle).
53:
42:
21:Covey (disambiguation)
512:rational expectations
464:
333:
321:
249:
169:
155:(who tend to sheep),
48:
36:
28:Herd (disambiguation)
1344:Spatial organization
1309:Decentralised system
1147:Sea turtle migration
1001:Swarming (honey bee)
587:List of animal names
524:contrarian investors
423:Energetic advantages
314:Collective vigilance
26:For other uses, see
1319:Group size measures
881:Biological swarming
552:Selfish herd theory
522:. "Contrarians" or
508:information cascade
419:in social animals.
308:selfish herd theory
268:behavioural ecology
140:, the generic term
111:are usually called
1334:Predator satiation
1195:Swarm (simulation)
1190:Swarm intelligence
1165:Agent-based models
996:Swarming behaviour
495:behavioral finance
471:
336:
328:
259:
200:maquis degradation
172:
107:. Large groups of
54:
43:
1367:
1366:
1354:Military swarming
1299:Animal navigation
1218:Collective motion
1205:Collective motion
1072:reverse migration
1006:Swarming motility
572:Primate sociality
518:, fear and greed
484:social psychology
388:risk of predation
232:socially dominant
1397:
1180:Crowd simulation
1157:Swarm algorithms
1128:Insect migration
1033:Animal migration
1025:Animal migration
1018:
943:Mobbing behavior
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748:
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709:
687:
681:
680:
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676:
671:on March 8, 2012
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369:Spinner dolphins
211:
187:
130:collective nouns
16:Similar as Group
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478:Human parallels
459:
451:
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415:in beehives or
404:
361:
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300:selfish herding
295:
293:Dilution effect
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1339:Quorum sensing
1336:
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1287:Related topics
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1273:Swarm robotics
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1250:Swarm robotics
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1084:Fish migration
1081:
1079:Cell migration
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1062:Bird migration
1059:
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1055:coded wire tag
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948:feeding frenzy
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700:(3): 465–479.
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488:herd behaviour
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68:. The form of
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1089:diel vertical
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926:herd behavior
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657:Duval, Clay.
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582:Pack (canine)
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577:Flock (birds)
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547:Herd behavior
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1294:Allee effect
1268:Nanorobotics
1258:Ant robotics
1235:Vicsek model
920:
827:
801:
788:
759:
746:
739:Group living
697:
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685:
673:. Retrieved
666:the original
652:
640:. Retrieved
620:
612:
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405:
392:
385:
379:In terms of
378:
374:Waggle dance
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337:
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296:
284:
264:sociobiology
260:
228:
224:
148:
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133:
127:
123:pack hunters
112:
96:
90:
82:
80:
73:
57:
55:
1314:Eusociality
1263:Microbotics
1133:butterflies
1104:sardine run
1038:altitudinal
960:pack hunter
503:speculators
395:competition
257:, Ethiopia.
255:Addis Ababa
251:Traffic jam
196:Overgrazing
194:in Greece.
1374:Categories
1228:clustering
1121:philopatry
1099:salmon run
1094:Lessepsian
636:0896085996
604:References
594:Literature
501:or market
408:infectious
324:snow goose
287:trade-offs
236:Group size
109:carnivores
50:Wildebeest
1349:Stigmergy
1329:Mutualism
989:bait ball
822:137–154).
675:April 13,
520:contagion
499:investors
469:, Morocco
467:Marrakech
340:vigilance
157:goatherds
153:shepherds
147:The word
119:predation
87:ungulates
81:The term
1380:Ethology
1278:Symbrion
1240:BIO-LGCA
1043:tracking
972:ant mill
914:sort sol
909:flocking
873:Swarming
642:30 March
537:Stampede
530:See also
417:grooming
413:propolis
365:foraging
359:Foraging
161:cowherds
128:Special
92:flocking
66:domestic
1390:Herding
1138:monarch
1067:flyways
1048:history
899:Droving
706:2006678
542:Herding
516:mimicry
442:mobbing
276:evolved
272:fitness
216:grazers
138:ecology
75:herding
1111:Homing
933:Locust
704:
633:
557:Herder
449:Mating
134:gaggle
95:, but
1175:Boids
1116:natal
904:Flock
702:JSTOR
669:(PDF)
662:(PDF)
192:goats
121:from
114:packs
105:goats
101:sheep
97:flock
39:sheep
955:Pack
921:Herd
677:2015
644:2015
631:ISBN
510:and
280:taxa
266:and
149:herd
142:herd
83:herd
62:wild
58:herd
627:146
103:or
64:or
1376::
814:^
772:^
714:^
698:80
696:.
629:.
322:A
125:.
56:A
865:e
858:t
851:v
708:.
679:.
646:.
202:.
30:.
23:.
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