Dienstag, 28 März 2023 14:37

MERZ, E. (1978)

Male-male interactions with dead infants in Macaca sylvanus.

Primates 19: 749–754. https://doi.org/10.1007/BF02373640

Arbeit durchgeführt in der Montagne des Singes, Kintzheim


Infants ofMacaca sylvanus are often involved in male-male interactions. Very similar interactions occur also with dead infants. The present paper describes male-male interactions with dead infants and emphasizes similarities and differences between these and those involving live infants. Causation is also briefly discussed.


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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


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.


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Intra-specific Variation in the Social Behavior of Barbary macaques (Macaca sylvanus).

Front. Psychol., Sec. Comparative Psychology 12. https://doi.org/10.3389/fpsyg.2021.666166

Arbeit durchgeführt in der La Montagne des Singes Kintzheim, im Tiergarten Nürnberg und im Zoo Cordoba.


Non-human primates show an impressive behavioral diversity, both across and within species. However, the factors explaining intra-specific behavioral variation across groups and individuals are yet understudied. Here, we aimed to assess how group size and living conditions (i.e., captive, semi-free-ranging, wild) are linked to behavioral variation in 5 groups of Barbary macaques (N=137 individuals). In each group, we collected observational data on the time individuals spent in social interactions and on the group dominance style, along with experimental data on social tolerance over food and neophobia. Our results showed that differences in group size predicted differences in the time spent in social interactions, with smaller groups spending a higher proportion of time in close spatial proximity, but a lower proportion of time grooming. Moreover, group size predicted variation in dominance style, with smaller groups being more despotic. Social tolerance was affected by both group size and living conditions, being higher in smaller groups and in groups living in less natural conditions. Finally, individual characteristics also explained variation in social tolerance and neophobia, with socially integrated individuals having higher access to food sources, and higher-ranking ones being more neophobic. Overall, our results support the view that intra-specific variation is a crucial aspect in primate social behavior and call for more comparative studies to better understand the sources of within-species variation.


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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.


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.


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Dienstag, 28 März 2023 13:18

PAUL, A. & KUESTER, J. (1996)

Infant handling by female Barbary macaques (Macaca sylvanus) at Affenberg Salem: testing functional and evolutionary hypotheses.

Behavioral Ecology and Sociobiology 39: 133–145. https://doi.org/10.1007/s002650050275.

Arbeit durchgeführt im Affenberg Salem


Assisting the genetic parents in the rearing of young, a widespread phenomenon in many birds and mammals, is usually regarded as an altruistic or mutualistic behavior. Infant handling by females other than the mother is also common in many primates, but due to high within- and between-species variation and limited knowledge about fitness consequences there is no consensus about its evolutionary and functional significance. Analysis of female infant-handling patterns and its reproductive consequences in three groups of semifree-ranging Barbary macaques revealed that nulliparous females significantly more often handled infants than parous females, but infant handling experience did not affect survival of their own first live-born offspring. Females interacted preferentially with closely related infants, but infant handling frequency improved neither infant survival nor maternal fecundity. Reciprocation of infant handling by mothers was rare. Although “aunting to death” occurred in the population, the hypothesis that infant handling serves to reduce the fitness of competitors was not supported. Limited evidence suggests that females at least sometimes use infants as strategic tools in the course of alliance formation. In concert with this poor evidence for a functional basis of the behavior, several lines of evidence support the hypothesis that infant handling evolved as a non-adaptive by-product of a strong selection for mother-offspring bonding. (1) Rates of infant handling were highest among females that experienced early infant loss. (2) Females caring for infants or yearlings of their own handled other infants significantly less often than females without dependent offspring. (3) Infant handling by females was most prevalent during the infants’ first month of life. (4) Both “aunting to death” and a successful adoption occurred irrespective of kinship relations. Although the by-product hypothesis appears to be the only one able to explain all results of this study, the apparent rarity of infant handling in non-female-bonded species suggest that kin selection is a possible alternative explanation for the evolution of female infant-handling in primates.


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Dienstag, 28 März 2023 13:12


The sociobiology of male–infant interactions in Barbary macaques, Macaca sylvanus.

Animal Behaviour 51 (1): 155-170. https://doi.org/10.1006/anbe.1996.0013.

Arbeit durchgeführt im Affenberg Salem.


Unlike most Old World monkeys, male Barbary macaques frequently associate with and care for infants shortly after birth. Three functional hypotheses have been proposed to explain male–infant interactions in this and other species. (1) The ‘paternal investment hypothesis’ proposes that males invest in their own progeny or otherwise related infants, (2) the ‘mating effort hypothesis’ proposes males care for infants to increase their access to mothers, and (3) the ‘agonistic buffering hypothesis’ proposes that males use infants to regulate their relations with other males. These hypotheses were tested using data on male–infant interactions, paternity and sexual behaviour obtained during a longitudinal study on Barbary macaques living in a large outdoor enclosure. Paternity of 91 infants was determined by DNA fingerprinting. Hypothesis 1 was not supported, because males did not preferentially interact with closely related infants. Similarly, hypothesis 2 was not supported because male caretakers were not more likely to sire the next infant of the mother than non-caretakers. Hypothesis 3 was supported because (1) the direction of at least one type of triadic interactions was significantly biased towards higher-ranking males, (2) the patterning of triadic interactions was strongly dependent on the rank distance between the males, and (3) interaction frequency increased significantly during periods of high inter-male tension. While kin relations were unimportant, the use of infants familiar with the opponent suggests that males make use of their knowledge of relationships between other group members. Beyond agonistic buffering, triadic interactions may serve an important function in coalition formation.


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Dienstag, 28 März 2023 13:08

PAUL, A. & THOMMEN, D. (1984)

Timing of Birth, Female Reproductive Success and Infant Sex Ratio in Semifree-Ranging Barbary Macaques (Macaca sylvanus).

Folia Primatologica 42 (1): 2-16. ISSN: 0015-5713 (Print); eISSN: 1421-9980 (Online).

Arbeit durchgeführt im Affenberg Salem.


Examined were 5 years of data on the reproduction of a semifree-ranging population of Barbary macaques (Macaca sylvanus). In this seasonally breeding species – birth season: mid-March to beginning of August – primiparous 4-year-old females gave birth significantly later in the year than older primiparous and multiparous females, respectively. Multiparous females without an infant from the preceding season gave birth significantly earlier than females who had raised an infant. 88.4% of birth intervals were approximately 1 year, 11.6% about 2 years. Infant loss did not influence the length of the interbirth interval, but after the birth of the next surviving infant the interval was significantly longer. The interval following the 1st infant was significantly longer than after subsequent infants. After the birth of daughters primiparous females had markedly longer birth intervals than after the birth of sons. Infant mortality was 9.1%. Neonatal mortality was influenced by rank and parity of the mother and sex of the infant. Allomothering and aggression by older group members are thought to be the main causes of infant mortality. Female reproduction rates were not dependent on rank. High-ranking females, however, bore their 1st infant significantly earlier than low-ranking females. Low-ranking females had more daughters than sons, in high-ranking females the reverse was found. Differences from findings of other species are discussed with regard to differences in social organization and the reproductive strategies resulting from them.


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Mittwoch, 15 Februar 2023 14:07

DOLLINGER, P. (2022)

Beobachtungen zur Aktivitätsverteilung und zum Ruheverhalten der afrikanischen Nashörner, Diceros bicornis (Linné, 1758) und Ceratotherium simum (Burchell, 1817), des Zürcher Zoos.

Zool. Garten N.F. 90 (2022): 161-182. doi:10.53188/zg008

Überarbeitete Fassung des nicht veröffentlichten Abschlussberichts vom 31.12.1970.

Volltext (PDF)


Es wurden 1,1 Ceratotherium simum simum und 0,2 Diceros bicornis michaeli des Zürcher Zoos während jeweils fünf Tagen und fünf Nächten hinsichtlich der Aktivitätsverteilung und des Schlafverhaltens beobachtet, wobei die Nachtbeobachtungen mit Hilfe eines Infrarot-Nachtsichtgeräts durchgeführt wurden.

Es werden einige qualitative Verhaltensbeobachtungen kurz beschrieben und mit Fotomaterial belegt. Die quantitativen Erhebungen ergaben einen sehr hohen, für die beiden Arten unterschiedlichen Anteil des Ruheverhaltens am Aktogramm (Breitmaulnashorn 64 %, Spitzmaulnashorn 52 %), das Vorhandensein einer biphasischen Aktivitätskurve bei beiden Arten mit Höhepunkten der Aktivität von 8-11 und von 14-17 Uhr, die Unterteilung der Ruhephasen in Intervalle von selten mehr als drei Stunden, ein regelmäßiges Alternieren von Links- und Rechtslage sowie bei allen Tieren eine Bevorzugung bestimmter Schlafstellen. Einige Beobachtungen weisen auf das Auftreten des paradoxen Schlafs bei den Nashörnern hin.


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Sonntag, 25 September 2022 09:42

LENGAGE, T. (2005)

Stimmanalyse beim Uhu Bubo bubo - eine Möglichkeit zur Individualerkennung.

Ornithol. Anzeiger 44: 91-97.

Volltext (PDF) 


Die Wiedererkennung von Individuen spielt bei sehr vielen Tierarten eine wichtige biologische Rolle. Denn für die meisten Vorgänge, an denen ein oder mehrere Individuen beteiligt sind, ist es notwendig, dass diese sich gegenseitig individuell erkennen können. Wenn also derartige individuell charakteristische Signale oft biologisch eine sehr wichtige Rolle spielen, können sie gleichermaßen für einen menschlichen Beobachter interessant sein. Denn sie erlauben es ihm, ein Individuum aus der Entfernung zu identifizieren, ohne es einfangen zu müssen. Die Auswertung der bei dieser Studie erhaltenen Daten zeigt, dass es möglich ist, Uhus sehr präzise anhand ihrer Rufe zu identifizieren. Denn der Uhu hat eine individuelle, charakteristische Stimme, die sich von einem Jahr zum anderen nicht ändert.


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BOVIDS: A deep learning-based software package for pose estimation to evaluate nightly behavior and its application to common elands (Tragelaphus oryx) in zoos.

Ecology and Evolution 12 (3): e8701. https://doi.org/10.1002/ece3.8701


Only a few studies on the nocturnal behavior of African ungulates exist so far, with mostly small sample sizes. For a comprehensive understanding of nocturnal behavior, the data basis needs to be expanded. Results obtained by observing zoo animals can provide clues for the study of wild animals and furthermore contribute to a better understanding of animal welfare and better husbandry conditions in zoos. The current contribution reduces the lack of data in two ways. First, we present a stand-alone open-source software package based on deep learning techniques, named Behavioral Observations by Videos and Images using Deep-Learning Software (BOVIDS). It can be used to identify ungulates in their enclosure and to determine the three behavioral poses “Standing,” “Lying—head up,” and “Lying—head down” on 11,411 h of video material with an accuracy of 99.4%. Second, BOVIDS is used to conduct a case study on 25 common elands (Tragelaphus oryx) out of 5 EAZA zoos with a total of 822 nights, yielding the first detailed description of the nightly behavior of common elands. Our results indicate that age and sex are influencing factors on the nocturnal activity budget, the length of behavioral phases as well as the number of phases per behavioral state during the night while the keeping zoo has no significant influence. It is found that males spend more time in REM sleep posture than females while young animals spend more time in this position than adult ones. Finally, the results suggest a rhythm between the Standing and Lying phases among common elands that opens future research directions.


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