Coalitions in male Barbary macaques, Macaca sylvanus: strength, success and rules of thumb.

Animal Behaviour 78 (2): 329-335. https://doi.org/10.1016/j.anbehav.2009.05.010

Arbeit durchgeführt im Affenberg Salem

Abstract:

Several quantitative models of coalition formation assume that a coalition is successful if the strength of the coalition is greater than the strength of the target, but unsuccessful otherwise. However, strong empirical evidence in favour of this hypothesis is still lacking. In this study, we provide an empirical test of this assumption in Barbary macaque males, by using a field-based estimate of individual competitive ability from which coalition strength is derived. Coalition success was determined for 90 coalitions composed of two partners and targeted at one male. Of these, 72.2% were behaviourally successful and 27.8% were unsuccessful. Asymmetry in strength was a significant predictor of coalition success, as this factor alone could explain up to 78.6% of coalition outcomes in the study group. Males behaved as if they were at least partially informed about the nature of this asymmetry. The targets of attacks by coalitions were more likely to counterattack as asymmetry in strength decreased, and coalition partners formed coalitions that produced on average a greater asymmetry in strength than would be expected by chance. However, we provide evidence that males may have used simple rules of thumb based on their knowledge of dyadic and third-party relationships, rather than estimates of asymmetry in strength per se. We conclude that competitive ability is an important factor in coalition formation in Barbary macaque males and discuss additional factors not included in this study, which may account for the unexplained outcomes.

bissonnette-biblio

Coalition formation among male Barbary macaques (Macaca sylvanus).

Am. J. Primatol. 50 (1):37–51. https://doi.org/10.1002/(SICI)1098-2345(200001)50:1<37::AID-AJP4>3.0.CO;2-3

Arbeit durchgeführt im Affenberg Salem.

Abstract:

A coalition is formed when one animal intervenes in an ongoing conflict between two parties to support one side. Since support of one party is also an act against the other party, coalitions are triadic interactions involving a supporter, a recipient, and a target. The purpose of this study was to test which of three possible theories explains coalition formation among male Barbary macaques: 1) Males support kin to enhance their indirect fitness (kin selection). 2) Males support nonkin to receive future reciprocal support (reciprocal altruism). 3) Males pursue self-interests and immediately benefit via nonkin support (cooperation). Coalition formation was investigated among 31 semi-free male Barbary macaques in the Salem Monkey Park, Germany during the mating season. The results show: 1) Males intervened more often in dyadic conflicts in which a related opponent was involved and supported related opponents more than unrelated opponents. Close kin supported each other more often than distant kin. 2) Some evidence for reciprocal support was found. However, reciprocity was probably a by-product of targeting the same individuals for dominance. 3) Coalition formation among nonkin is best interpreted as cooperation, based on self-interests. Male Barbary macaques seem to intervene more often to stabilize and less often to improve their rank. Although our data were limited, the results revealed that kin support, reciprocal support, and cooperative support were all involved in coalition formation among male Barbary macaques.

widdig-biblio

Factors influencing seasonal changes in the herd size and composition of swamp deer in Jhilmil Jheel Conservation Reserve, Haridwar, Uttarakhand, India.

Int. J. of Pharm. & Life Sci. (IJPLS), Vol. 4, Issue 8: Aug: 2013: 2870-2875
2871. ISSN: 0976-7126.

Abstract:

A small population of swamp deer (320 in number) was recently rediscovered in Uttarakhand state (in 20 05) at Jhilmil Jheel (Sinha et al. 2006). Seasonal variation in herd size and composition of vulnerable swamp deer (Rucervus duvaucelii duvaucelii) were studied in this area using scan sampling technique. Largest herds (13) and highest male to female ratio (145:100) were observe d during summer when deer congregate. Smallest herd s were reported in monsoon due to poor sighting in dense vegetation cover. In monsoon, pregnant adult females observed to separate from the herds. The fawn to female ratio was highest in winters (59:100), as fawns were big enough to follow the mothers. It was concluded that the population structure variables are therefore most suitable tools to assess impact of habitat changes on swamp deer populations.

tewari-biblio

Male tolerance and male-male bonds in a multilevel primate society.

PNAS, Published online before print, September 8, 2014. doi:10.1073/pnas.1405811111.

Abstract:

Male relationships in most species of mammals generally are characterized by intense intrasexual competition, with little bonding among unrelated individuals. In contrast, human societies are characterized by high levels of cooperation and strong bonds among both related and unrelated males. The emergence of cooperative male–male relationships has been linked to the multi-level structure of traditional human societies. Based on an analysis of the patterns of spatial and social interaction in combination with genetic relatedness data of wild Guinea baboons (Papio papio), we show that this species exhibits a multilevel social organization in which males maintain strong bonds and are highly tolerant of each other. Several “units” of males with their associated females form “parties”, which team up as “gangs”.

Several gangs of the same “community” use the same home range. Males formed strong bonds predominantly within parties; however, these bonds were not correlated with genetic relatedness. Agonistic interactions were relatively rare and were restricted to a few dyads. Although the social organization of Guinea baboons resembles that of hamadryas baboons, we found stronger male–male affiliation and more elaborate greeting rituals among male Guinea baboons and less aggression toward females. Thus, the social relationships of male Guinea baboons differ markedly from those of other members of the genus, adding valuable comparative data to test hypotheses regarding social evolution. We suggest that this species constitutes an intriguing model to study the predictors and fitness benefits of male bonds, thus contributing to a better understanding of the evolution of this important facet of human social behavior.

patzelt-biblio

Social organization, distribution and movements of a migratory guanaco population in the Chilean Patagonia.

Revista Chilena de Historia Natural 68: 489-500.

Abstract:

Herein we document the distribution, movement, and social organization of a guanaco (Lama guanicoe) population in a 25-km² area at Torres del Paine National Park in southern Chile. In 1980, the population was censused 28 times. Four socioecological periods were recognized: summer territorial, fall transitional, winter aggregational, and spring transitional. Family groups, male groups, solo males, mixed groups, and female groups were the major social units recognized. Guanacos spent the summer in the east region, migrating 12 km to the west region during winter. Family groups (53% of all animals), male groups (35%) and solo male (8%) were the main social units in summer, and mixed groups (80%) in winter. Snow cover and availability of forage were the suspected causes of seasonal migratory movements, that in turn greatly influenced social organization, group size, and composition.

ortega-biblio

Entwicklung der räumlichen und sozialen Organisation von Przewalskipferden (E. ferus przewalskii) unter naturnahen Bedingungen im Pentezuggebiet (Hortobágy Nationalpark, Ungarn).

Dr. rer. nat. Disseration

210 Seiten

Ganzer Text

Mathematisch-Naturwissenschaftliche Fakultät der Universität Köln
Betreuung: Prof. Dr. Gunther Nogge und Dr. Lydia Kolter, Kölner Zoo.
In Zusammenarbeit mit dem Kölner Zoo

Zusammenfassung:

Ziel dieser Arbeit war es, die Entwicklung der räumlichen und sozialen Organisation sowie die Nutzungsmuster von drei Haremsgruppen von Przewalskipferden zu ermitteln, die nacheinander in das 2400 ha große Pentezuggebiet im Hortobágy Nationalpark (Ungarn) entlassen wurden. Anhand von Ergebnissen aus Studien an Equiden wurden zunächst Erwartungen formuliert, die Ergebnisse in der vorliegenden Arbeit mit ihnen verglichen und für Vorhersagen über den wachsenden Einfluß der Przewalskipferdpopulation auf das Pentezuggebiet herangezogen. Aus den ersten beiden Harems entstand durch Übernahme ein großer Verband. Nach dem Tod des Haremshengstes dieser Gruppe übernahm der von ihm vorher besiegte und zu der Zeit einzige Hengst in Pentezug die große Gruppe. Im Herbst 2000 schlossen sich abgewanderte Hengste zu einer Junggesellengruppe zusammen. Die Haremsgruppen in Pentezug hatten im Frühjahr, Sommer und Herbst feste Freß- und Ruhephasen. Diese Tagesrhythmen unterschieden sich bei den Haremsgruppen im Sommer signifikant. Eine saisonale Änderung bezüglich der Nutzung des Aktionsraums ist bei den Mitgliedern der großen Gruppe in den Jahren von 1998-2000 nur ansatzweise im Herbst zu erkennen, jedoch traten solche Änderungen auch in Verbindung mit dem jeweils neu die Gruppe übernehmenden Haremshengst auf. Die Mitglieder der Gruppe Makan dagegen nutzten ihren Aktionsraum entsprechend der Jahreszeiten saisonal unterschiedlich. Alle Pferde der drei Gruppen in Pentezug wurden deutlich öfter auf Kurzgras beobachtet als auf Langgras. Die Pferde präferierten in Ruhe-, z.T. aber auch in Freßphasen die alten, dunklen und kühlen Ställe in ihren Aktionsräumen, vermutlich um Schutz vor Insekten zu suchen. Die nährstoffreiche Ruderalvegetation wurde von den Pferden der großen Gruppe und der Gruppe Makan bis auf zwei Ausnahmen während des gesamten Beobachtungszeitraums in Freßphasen präferiert. Durch den Huftritt der Pferde entstandene Wechsel verbanden die Freß- und Ruheplätze, oft nutzten die Tiere aber die schon vorhandenen Wege. Die unterschiedlichen Gruppen von Przewalskipferden in Pentezug nutzten bis auf eine vorübergehende Ausnahme exklusive Aktionsräume, zwischen denen eine größtmögliche Distanz lag. In diesen Aktionsräumen gab es immer einen alten Schafstall, der von Ruderalvegetation umgeben war. Die Aufenthaltsorte der Pferde konzentrierten sich um die alten Ställe und die Ruderalflächen. Die Gruppenzugehörigkeit der adulten Stuten der beiden Haremsverbände in Pentezug blieb während der dreijährigen Beobachtungszeit trotz Veränderungen in der Gruppenzusammensetzung durch Übernahmen, Zu- und Abwanderungen und den Tod dreier Stuten relativ stabil. Die Dominanzverhältnisse der Mitglieder der großen Gruppe und der Junggesellengruppe waren polygonal. Das lineare Dominanzverhältnis der Pferde der Gruppe Makan änderten sich temporär mit der Geburt ihrer Fohlen zu Gunsten der Stute. Innerhalb aller Gruppen blieben einige Dominanzverhältnisse zwischen Pferden ungeklärt, hauptsächlich deshalb, weil diese nicht agonistisch miteinander interagierten. Möglicherweise handelte es sich hierbei um eine subtile Form des Ausweichens. Die Häufigkeit der Nächsten Nachbarschaften und die Präferenz für dieselben Untergruppen wiesen sowohl auf die ursprüngliche Zusammensetzung der Stuten der ersten beiden ins Gebiet entlassenen Harems hin, als auch auf Bindungen zwischen den Gruppenmitgliedern. Bei Veränderung in ihrem Umfeld reduzierten die Pferde der großen Gruppe die zunächst stark angestiegene Rate der agonistischen Aktionen/Stunde/Pferd nach einiger Zeit, indem sie sich gemäß ihrer Bindungsverhältnisse in Untergruppen aufteilten und vermehrt nicht-agonistisches Verhalten zeigten. Die Junggesellengruppe wurde zu kurz beobachtet, um die Sozialstruktur genau zu erfassen. In allen drei beobachteten Gruppen gab es Tendenzen, die auf eine Rollenübernahme ranghoher und starker Pferde hinwiesen. Diese sicherten häufiger und veranlaßten die anderen Gruppenmitglieder auch öfter zu Ortswechseln. Außerdem beschützten sie schwächere Pferde vor Angreifern. Zwischen den unterschiedlichen Haremshengsten im Gebiet konnte keine Dominanzhierarchie festgestellt werden, jedoch wurde der älteste Junggeselle von einem der Haremshengste deutlich dominiert. Territorialverhalten wurde in der dreijährigen Beobachtungszeit bei keinem der Hengste festgestellt. Auch das Markierungsverhalten der Hengste stand nicht im Zusammenhang mit Territorialverhalten. Die Pferde markierten häufig aufgesuchte Orte, und die Kothaufen dienten daher vermutlich zum einen der Orientierung, zum anderen der Übermittlung sozial relevanter Informationen. Ein Einfluß der noch sehr kleinen Population von Przewalskipferden auf das Gebiet war bisher nur auf den Flächen mit Ruderalvegetation sichtbar, die von den Pferden präferiert und kurzgehalten wurden. Wahrscheinlich werden sich bei andauerndem Weidedruck die Pflanzenzusammensetzung und die Produktivität dieser Flächen verändern.

Abstract:

The aim of this work was to study the development of the spatial and social organization as well as the habitat use of three harem groups of Przewalski´s horses living under almost natural conditions. The groups were introduced to the 2400 ha sized Pentezug area in the Hortobágy National Park (Hungary) successively. Hypotheses were derived from other studies on equids and the results of this work were compared to them. The latter were also used to make predictions on the growing impact of the Przewalski´s horse population on Pentezug. The first two harem groups were combined to one big group due to a fight between the harem stallions. Soon after the fight the winner died and the remaining male took over the big group. In autumn 2000 dispersed stallions built a bachelor group. The harem groups in Pentezug had clear activity patterns concerning feeding and resting periods during spring, summer and autumn. In the summer these activity patterns differed significantly between the harems. The groups in Pentezug were observed more often on short grass than on long grass areas. Probably to avoid insects the horses preferred to use the dark and rather cool old stables still existing in the area during resting and partly during feeding periods. The harem members almost always preferred to stay on the most nutritious vegetation type in Pentezug during the feeding periods: Onopordion-Hordaetum hystricis. Trails made by the horses connected feeding and resting sites, but the animals frequently moved on existing roads. With one temporary exception the different groups of Przewalski´s horses in Pentezug used exclusive home ranges which were seperated by the largest possible distance. The home ranges always included an old stable surrounded by the vegetation type Onopordion-Hordaetum hystricis and the horses concentrated around theses areas. The memberships of adult mares in the remaining two harem groups in Pentezug were rather stable during the three years of the study. This was observed although the composition of the groups changed by other harem stallions taking over the big group, dispersal and mortality. The dominance relationships of the horses of the big group and of the bachelor group were polygonal, whereas in Makan´s harem group they were mainly linear. The mare dominated the stallion temporarily after the birth of her foal. Some of the dominance relationships remained unclear mainly because the horses did not show any agonistic interactions. This phenomenon may be a subtle form of avoiding. The frequency of neighbourhood between the members of the big group and the composition of the subgroups showed reference to the original composition of the first two harems released into Pentezug as well as to social bonds between the animals. Changes in the environment of the big group caused the rate of agonistic interactions per hour and per horse to increase at first. After a while the animals reduced this rate by dividing into subgroups according to their bonds. Within the subgroups non-agonistic behaviour patterns increased while the rate of agonistic interactions/h/horse decreased to the "normal" level. The observation period for the bachelors was too short to gain precise insight into the social structure of this group. Within all three groups in Pentezug dominant horses showed tendencies to be responsible for vigilance and/or for initiating the other group members to change locations as well as for protecting weak horses. No dominance hierarchy could be found between the harem stallions in Pentezug, but the oldest male of the bachelor group was dominated by the harem stallion of the big group. The stallions were not territorial during the course of this study and marking behaviour did not seem to be related to territoriality. Fecal piles most probably served for transmitting socially relevant information and for orientation since the stallions marked places that they visited quite frequently. Up to now the impact of the small population of Przewalski´s horses on Pentezug is only visible on areas covered by Onopordion-Hordaetum hystricis. The horses showed preference for this vegetation type, so these areas were under grazing pressure. Probably this will lead to changes in plant composition and productivity of this vegetation type in the future.

roth-biblio