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Sigurjonsdottir, H., Thorhallsdottir, A., Hafthorsdottir, H., & Granquist S. (2012). The Behaviour of Stallions in a Semiferal Herd in Iceland: Time Budgets, Home Ranges, and Interactions. International Journal of Zoology, 2012(Article ID 162982).
Abstract: A permanent herd of Icelandic horses with four stallions and their harems was studied for a total of 316 hours in a large pasture (215 ha) in May 2007 in Iceland. Interactions between stallions of different harems and other aspects of the horses' behaviour were studied. One stallion and nine horses were introduced into the pasture prior to the study to examine the reactions of the resident stallions to a newcomer. The stallions spent significantly less time grazing than other horses and were more vigilant. Home ranges overlapped, but harems never mixed. The stallions prevented interactions between members of different harems indirectly by herding. Generally, interactions between resident stallions were nonviolent. However, encounters with the introduced stallion were more aggressive and more frequent than between the other stallions. Here, we show that four harems can share the same enclosure peacefully. The social network seems to keep aggression at a low level both within the harems and the herd as a whole. We encourage horse owners to consider the feasibility of keeping their horses in large groups because of low aggression and because such a strategy gives the young horses good opportunities to develop normally, both physically and socially.
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Leadbeater, E. (2015). What evolves in the evolution of social learning? J Zool, 295(1), 4–11.
Abstract: Social learning is fundamental to social life across the animal kingdom, but we still know little about how natural selection has shaped social learning abilities on a proximate level. Sometimes, complex social learning phenomena can be entirely explained by Pavlovian processes that have little to do with the evolution of sociality. This implies that the ability to learn socially could be an exaptation, not an adaptation, to social life but not that social learning abilities have been left untouched by natural selection. I discuss new empirical evidence for associative learning in social information use, explain how natural selection might facilitate the associative learning process and discuss why such studies are changing the way that we think about social learning.
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King, S. R. B., & Gurnell, J. (2007). Scent-marking behaviour by stallions: an assessment of function in a reintroduced population of Przewalski horses (Equus ferus przewalskii). J Zool, 272(1), 30–36.
Abstract: Abstract Scent marking is a common form of intraspecific communication in mammal species, and using faeces or urine is a cost-effective way of signalling competitive ability and resource holding power. Marking is ritually performed by male equids, and here we assess the function of male scent-marking behaviour in a recently introduced population of Przewalski horses Equus ferus przewalskii in Mongolia. Two forms of scent marking were observed: defecation on stud piles formed from repeated dunging in the same place, and overmarking of faeces and urine of mares. Stud piles were marked with dung by the harem holder and sniffed before and after dung was deposited. They were not found specifically at the periphery of harem ranges but occurred for the most part along routes used by the horses, and were more common in the core parts of harem ranges or where harem ranges overlapped. Thus, rather than being used to defend range boundaries, stud piles were placed predominantly where they would be encountered by male intruders. Mare excreta were covered with urine by the stallion, but were only sniffed before they were marked, not after. These marks appear to advertise to the mare and other, intruding stallions that the harem holder was the mare's consort and that the interloper should not risk trying to steal the mare or sneak a mating. Thus, the two forms of marking by harem holders appear to combine as first and second lines of defence of paternity rights in male intrasexual competition.
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de Villiers, M. S., Richardson, P. R. K., & van Jaarsveld, A. S. (2003). Patterns of coalition formation and spatial association in a social carnivore, the African wild dog (Lycaon pictus). J Zool, 260(4), 377–389.
Abstract: In many social species, relationships within groups seem to be non-random but related to variables such as rank, kinship or sexual attractiveness. The endangered African wild dog Lycaon pictus is a social carnivore that lives in large, stable packs, and intra-pack associations might be expected to display similar patterns. We investigated patterns of coalition formation (support during dominance interactions, and partnership interactions) and resting associations between members of a captive pack of 19 wild dogs. The social organization of the captive pack was similar to that of free-ranging packs in many respects. Polyadic (group) incidents of coalition support were also observed in a free-ranging pack. Patterns of coalition formation in the captive pack were related to rank. Most aggressive interactions involved high-ranking individuals (particularly the alpha, beta and third-ranking males) and coalitionary support tended to reinforce the existing hierarchy. However, there was at least one example of support influencing a successful rank challenge. Support was affected by potential risks and benefits, the latter including dominance through association and revolutionary alliances. An even stronger pattern overlaid associations between pack members: coalitions and resting associations were strongest between members of the same age–sex cohort, and may have enabled the eventual dominance of younger pack members over adults. Among adults, coalitionary associations were sometimes overridden by intersexual relationships. The results from this captive pack suggest that wild dogs are sensitive to differences in competitive ability. This information, in conjunction with strong affiliative bonds between littermates, is used to manoeuvre for position in the social hierarchy. It may also be important during dispersal, in encounters with other dispersing groups of the same sex. Although most features of the social structure of the captive pack were comparable to those of free-ranging packs, aspects such as the influence of relatedness on coalition formation still need to be explored.
Keywords: coalitions; social systems; Carnivora; Lycaon pictus
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Mace, G. M., Harvey, P. H., & Clutton-Brock, T. H. (1981). Brain size and ecology in small mammals. J Zool, 193(3), 333–354.
Abstract: Relative brain size (measured as gross brain size after body size effects are removed) differs systematically between families of rodents, insectivores and lagomorphs. The Sciuridae have the largest relative brain size, the Soricidae and Bathyergidae the smallest. These results are discussed and compared with previous analyses of relative brain sizes among primates and bats. These differences complicate comparisons between relative brain size across phylogenetically diverse species and attempts to relate differences in relative brain size to ecological variables. To overcome these problems, best fit relationships were estimated for each family, and values for each genus were expressed as deviations from the lines of best fit. We refer to these values as Comparative Brain Size (CBS). Differences in CBS are related to differences in habitat type (forest-dwelling genera have larger CBS' than grassland forms), in diet (folivores have smaller CBS' than generalists or insectivores, frugivores and granivores), in zonation (arboreal genera have larger CBS' than terrestrial ones) and in activity timing (nocturnal genera have larger CBS' than dirurnal ones). However, these ecological categories are interrelated and, when the effects of other ecological differences are taken into account using analyses of variance, only the differences associated with diet, and possibly habitat remain.
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Clutton-Brock, T. H., & Harvey, P. H. (1980). Primates, brains and ecology. J. Zool. Lond., 190(3), 309–323.
Abstract: The paper examines systematic relationships among primates between brain size (relative to body size) and differences in ecology and social system. Marked differences in relative brain size exist between families. These are correlated with inter-family differences in body size and home range size. Variation in comparative brain size within families is related to diet (folivores have comparatively smaller brains than frugivores), home range size and possibly also to breeding system. The adaptive significance of these relationships is discussed.
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Alexander, R., MCN et al. (1977). Fast locomotion of some african ungulates. J Zool, 183(3), 291–300.
Abstract: ABSTRACT
Ten species of ungulate were filmed, galloping in their natural habitat. They ranged in size from Thomson's gazelle (about 20 kg) to giraffe (about 1000 kg). They were pursued to make them run as fast as possible. The films have been analysed to determine speed, stride frequency, stride and step lengths, and duty factors. The dependence of these quantities on body size is discussed. Summary: Fast locomotion of zebra, giraffe, warthog and seven species of Bovidae has been studied. The animals were filmed from a pursuing vehicle while galloping in their natural habitat. Stride frequency was more closely correlated with limb length (represented by hip height) than with body mass. Mean stride frequency was proportional to (hip height)-0·51 and maximum stride frequency to (hip height) -0·63. Maximum speed was between 10 and 14 m s -1 for all species except buffalo (7 m s -1). It was not significantly correlated with body mass. Since the small species ran at least as fast as the large ones they attained higher Froude numbers. Relative stride length was approximately 1·8 (Froude number)0·39 for all species, irrespective of size. Relative step length was approximately 0·65 (Froude number)0·2, both for the fore feet and for the hind ones. The vertical forces exerted by the feet are proportional to (body weight)×(Froude number)0·2 so the forces at maximum speed are larger multiples of body weight for small species than for large ones. |
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Geisbauer, G., Griebel, U., Schmid, A., & Timney, B. (2004). Brightness discrimination and neutral point. Can. J. Zool, 82(4), 660–670.
Abstract: Abstract: Equine brightness discrimination ability and color discrimination were measured using a two-choice discrimination
task. Two Haflinger horses (Equus caballus L., 1758) were trained to discriminate 30 different shades of grey varying from low to high relative brightness. Their ability to distinguish shades of grey was poor, with calculated Weber fractions of 0.42 and 0.45. In addition, a “neutral point” test to determine the dimensionality of color vision was carried out. Three hues of blue-green were tested versus a range of grey targets with brightnesses similar to those of the blue-green targets. A neutral point was found at about 480 nm. Thus, we can conclude that horses possess dichromatic color vision. |
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Peterson R.O., Jacobs A.K., Drummer T.D., Mech L.D., & Smith D.W. (2002). Leadership behavior in relation to dominance and reproductive status in gray wolves, Canis lupus. Canadian Journal of Zoology, 80, 1405–1412.
Abstract: We analyzed the leadership behavior of breeding and nonbreeding gray wolves (Canis lupus) in three packs during winter in 1997-1999. Scent-marking, frontal leadership (time and frequency in the lead while traveling), initiation of activity, and nonfrontal leadership were recorded during 499 h of ground-based observations in Yellowstone National Park. All observed scent-marking (N = 158) was done by breeding wolves, primarily dominant individuals. Dominant breeding pairs provided most leadership, consistent with a trend in social mammals for leadership to correlate with dominance. Dominant breeding wolves led traveling packs during 64% of recorded behavior bouts (N = 591) and 71% of observed travel time (N = 64 h). During travel, breeding males and females led packs approximately equally, which probably reflects high parental investment by both breeding male and female wolves. Newly initiated behaviors (N = 104) were prompted almost 3 times more often by dominant breeders (70%) than by nonbreeders (25%). Dominant breeding females initiated pack activities almost 4 times more often than subordinate breeding females (30 vs. 8 times). Although one subordinate breeding female led more often than individual nonbreeders in one pack in one season, more commonly this was not the case. In 12 cases breeding wolves exhibited nonfrontal leadership. Among subordinate wolves, leadership behavior was observed in subordinate breeding females and other individuals just prior to their dispersal from natal packs. Subordinate wolves were more often found leading packs that were large and contained many subordinate adults.
Nous avons analysé le comportement de commandement chez des loups gris (Canis lupus) reproducteurs et non reproducteurs appartenant à trois meutes durant les hivers de 1997-1999. Le marquage d'odeurs, la position en tête de meute (la durée et la fréquence au cours des déplacements), l'initiation des activités et la prise de décisions ailleurs qu'en tête du groupe ont été notés pendant 499 h d'observations au sol dans le Parc national de Yellowstone. Tous les marquages (N = 158) ont été faits par des loups reproducteurs, surtout des individus dominants. Ce sont surtout les couples dominants qui assurent le commandement, en accord avec une tendance chez les mammifères sociaux chez lesquels la fonction de chef est en corrélation avec la dominance. Les loups reproducteurs dominants ont conduit les meutes en déplacement pendant 64 % (N = 591) des épisodes de comportement et pendant 71 % des épisodes de déplacement (N = 64 h). Les mâles et les femelles reproducteurs ont dirigé les meutes en déplacement à peu près également, ce qui reflète probablement l'investissement parental important aussi bien de la part des reproducteurs mâles que des femelles. Les comportements nouveaux (N = 104) ont été adoptés presque trois fois plus souvent par des reproducteurs dominants (70 %) que par des individus non reproducteurs (25 %). Des femelles reproductrices dominantes ont été instigatrices des activités de leur meute environ quatre fois plus souvent que les femelles reproductrices subordonnées (30 vs. 8 fois). Bien qu'une femelle reproductrice subordonnée ait pris la direction de sa meute plus souvent que les individus non reproducteurs au cours d'une saison, cela n'est pas habituel. Dans 12 cas, des loups reproducteurs ont pris la direction de leur meute sans être en tête. Chez les individus subordonnés, le comportement de commandement a été observé chez des femelles reproductrices et chez d'autres individus juste avant qu'ils ne quittent leur meute d'origine au moment de la dispersion. Les loups subordonnés mènent surtout de grands troupeaux qui comptent beaucoup d'individus subordonnés.[Traduit par la Rédaction] |
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Weckerly, F. W. (1999). Social bonding and aggression in female Roosevelt elk. Can J Zool, 77(9), 1379–1384.
Abstract: Abstract: The relationship between degree of social bonding (extent of association among individuals) and level of aggression in ruminants is unclear. I examined social bonding and aggression in three groups of female Roosevelt elk (Cervus elaphus roosevelti) over 2 years. I hypothesized that when animals are socially bonded, bouts of aggression will be won by the individual initiating the aggression, occur quickly, and involve little physical contact, and the level of aggression does not correlate with group size. The degree of social bonding was high among individuals in all groups. Dyads of known individuals were together >80% of the time. A permutation analysis indicated that groups with the observed sizes had <0.001 chance of random association, except on one occasion when the probability was 0.72 for one group. Using focal-animal sampling, aggressive interactions were won 72% of the time by the initiator, occurred quickly (<5 s), and involved little physical contact, and the level of aggression was not correlated with group size. The level of aggression was, however, significantly lower in one of the groups. This group may have had access to more abundant food resources than the other groups. Socially bonded elk conducted aggressive interactions in a fashion that did not disrupt social stability. Résumé : La relation entre le degré de liaison sociale (importance des associations entre individus) et l`agressivité n`est pas claire chez les ruminants. J`ai étudié les liaisons sociales et l`agressivité chez trois groupes de femelles du Cerf de Roosevelt (Cervus elaphus roosevelti) pendant 2 ans. J`ai posé en hypothèse que, chez les animaux liés socialement, la victoire devrait être emportée par l`individu qui entreprend l`agression, l`agression devrait être de courte durée, se faire avec peu de contacts physiques et la fréquence des agressions ne devrait pas être liée à la taille du groupe. Des paires d`individus passaient plus de 80% de leur temps ensemble. Une analyse des permutations a démontré que, chez les groupes des tailles observées, la probabilité d`une association aléatoire était de moins de 0,001, sauf en un cas où cette probabilité a été évaluée à 0,72 chez un groupe. Par échantillonnage directionnel, j`ai observé que les interactions agressives étaient gagnées par l`individu attaquant 72% du temps, étaient de courte durée (<5 s), se faisaient avec peu de contacts physiques et leur fréquence n`était pas reliée à la taille du groupe. Il y avait cependant moins d`agressivité chez l`un des groupes. Il se peut que ce groupe ait eu accès à plus de ressources alimentaires que les autres. Chez les cerfs liés par des liens sociaux, l`agressivité ne se manifeste pas de façon à déséquilibrer la stabilité sociale.
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