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| Author | Berger, J. | ||||
| Title | Organizational systems and dominance in feral horses in the Grand Canyon | Type | Journal Article | ||
| Year | 1977 | Publication | Behavioral Ecology and Sociobiology | Abbreviated Journal | Behav. Ecol. Sociobiol. |
| Volume | 2 | Issue | 2 | Pages | 131-146 |
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| Abstract | 1. Several aspects of the behavioral ecology of feral horses (Equus caballus) were studied in Grand Canyon, Arizona, USA. Most bands contained three to five horses that included one stallion and his harem. Males that did not obtain a harem remained solitary. Throughout the study bands remained stable in composition. 2. Home ranges for all bands decreased in size in successive warm months, probably due to increased ambient temperature and drought. This resulted in greater utilization of spring areas that led to increased interband confrontation and agonistic display. 3. Territoriality was not observed in individual horses or bands, but bands hierarchial in both inter- and intraband structures. Interband stallion dominance was reinforced through posturing and fighting. Intraband hierarchies, as determined by dominance coefficients, were independent of individual size in three of four bands. 4. Indexes of nervousness (NER), calculated while horses were drinking, showed that stallions were less nervous than mares. A low NER was correlated with individuals leading toward drinking areas, whereas a high NER existed in individuals initiating flight although no single horse acted consistently as a leader. 5. Diurnal activity patterns were correlated with ambient temperatures. |
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| Notes | Approved | no | |||
| Call Number | refbase @ user @ | Serial | 748 | ||
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| Author | Dugatkin, L.A. | ||||
| Title | Winner and loser effects and the structure of dominance hierarchies | Type | Journal Article | ||
| Year | 1997 | Publication | Behavioral Ecology | Abbreviated Journal | Behav. Ecol. |
| Volume | 8 | Issue | 6 | Pages | 583-587 |
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| Abstract | In the literature on dominance hierarchies, “winner” and “loser” effects usually are denned as an increased probability of winning at time T, bated on victories at time T-l, T-2, etc, and an increased probability of losing at time T, based on losing at T-1, T-2, etc., respectively. Despite some early theoretical work on winner and loser effects, these factors and how they affect the structure of dominance hierarchies have not been examined in detail. I developed a computer simulation to examine winner and loser effects when such effects are independent of one another (as well as when they interact) and when combatants assess each other's resource-holding power. When winner effects alone were important, a hierarchy in which all individuals held an unambiguous rank was found. When only loser effects were important, a dear alpha individual always emerged, but the rank of others in the group was often unclear because of the scarcity of aggressive interactions. Increasing winner effects for a given value of the loser effect increase the number of individuals with unambiguous positions in a hierarchy and the converse is true for increasing the value of the loser effect for a given winner effect Although winner and loser effects have been documented in a number of species, no study has documented both winner and loser effects (using some controlled, pairwise testing system) and the detailed nature of behavioral interactions when individuals are in groups. I hope the results of this model will spur such studies in the future. | ||||
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| Notes | 10.1093/beheco/8.6.583 | Approved | no | ||
| Call Number | refbase @ user @ | Serial | 759 | ||
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| Author | Cant, M.A.; Field, J. | ||||
| Title | Helping effort in a dominance hierarchy | Type | Journal Article | ||
| Year | 2005 | Publication | Behavioral Ecology | Abbreviated Journal | Behav. Ecol. |
| Volume | 16 | Issue | 4 | Pages | 708-715 |
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| Abstract | In many cooperatively breeding species, group members form a dominance hierarchy or queue to inherit the position of breeder. Models aimed at understanding individual variation in helping behavior, however, rarely take into account the effect of dominance rank on expected future reproductive success and thus the potential direct fitness costs of helping. Here we develop a kin-selection model of helping behavior in multimember groups in which only the highest ranking individual breeds. Each group member can invest in the dominant's offspring at a cost to its own survivorship. The model predicts that lower ranked subordinates, who have a smaller probability of inheriting the group, should work harder than higher ranked subordinates. This prediction holds regardless of whether the intrinsic mortality rate of subordinates increases or decreases with rank. The prediction does not necessarily hold, however, where the costs of helping are higher for lower ranked individuals: a situation that may be common in vertebrates. The model makes two further testable predictions: that the helping effort of an individual of given rank should be lower in larger groups, and the reproductive success of dominants should be greater where group members are more closely related. Empirical evidence for these predictions is discussed. We argue that the effects of rank on stable helping effort may explain why attempts to correlate individual helping effort with relatedness in cooperatively breeding species have met with limited success. | ||||
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| Notes | 10.1093/beheco/ari051 | Approved | no | ||
| Call Number | refbase @ user @ | Serial | 760 | ||
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| Author | Vahl, W.K.; Lok, T.; van der Meer, J.; Piersma, T.; Weissing, F.J. | ||||
| Title | Spatial clumping of food and social dominance affect interference competition among ruddy turnstones | Type | Journal Article | ||
| Year | 2005 | Publication | Behavioral Ecology | Abbreviated Journal | Behav. Ecol. |
| Volume | 16 | Issue | 5 | Pages | 834-844 |
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| Abstract | In studying the success of foraging animals, studies of interference competition have put emphasis on effects of competitor density, whereas studies of resource defense have focused on the effects of the spatial distribution of food within patches. Very few studies have looked at both factors simultaneously, that is, determined whether the effects of competitor density on foraging success depend on the spatial distribution of food. We studied the behavior and the foraging success of ruddy turnstones (Arenaria interpres) using an experiment in which we varied both the presence of a competitor and the food distribution. Because turnstones may differ strongly in their relative dominance status, we also experimentally varied the foragers' relative dominance status. We found that the presence of a competitor only reduced the foraging success of subordinate birds foraging at the clumped food distribution. At this condition, dominant and subordinate birds differed markedly in their foraging success. Contrary to our expectations, we did not observe more agonistic behavior at the clumped food distribution. This indicates that the amount of agonistic behavior observed may be a bad indicator of interference effects. These findings have specific implications for models of interference competition. Most notably they show that the effects of competitor density on agonistic behavior and foraging success may well depend on the spatial distribution of food and the foragers' relative dominance status. Additionally, our results suggest that social dominance will not be fully understood without considering long-term processes such as the formation and maintenance of social dominance hierarchies. | ||||
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| Notes | 10.1093/beheco/ari067 | Approved | no | ||
| Call Number | refbase @ user @ | Serial | 761 | ||
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| Author | Ginsberg, J. R; Rubenstein, D. I. | ||||
| Title | Sperm competiton and variation in zebra mating behaviour | Type | Journal Article | ||
| Year | 1990 | Publication | Behavioral Ecology and Sociobiology | Abbreviated Journal | Behav. Ecol. Sociobiol. |
| Volume | 26 | Issue | 6 | Pages | 427-434 |
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| Abstract | Data are presented on the breeding behavior of two zebra species to test whether intra- and interspecific variation in male reproductive behavior and physiology are correlated with differences in female promiscuity. In one species, plains zebra (Equus burchelli) females live in closed membership single male groups and mate monandrously. In the other species, the Grevy's zebra (E. grevyi) females live in groups whose membership is much more temporary. Typically, associations with individual males are brief and mating is polyandrous. However, some females – those having just given birth – reside with one male for long periods, mating monandrously. These differences in female mating behavior generate variability in the potential for sperm competition. We show that behavioral differences in male investment in reproductive activities correlate with the potential for sperm competition. When mating with promiscuous mares, Grevy's zebra stallions made a greater investment in reproductive behavior (calling, mounting, ejaculations) than did stallions of either species when mating with monandrous females. The evolution of large testes size in the Grevy's zebra, when compared to the congeneric plains zebra, horse, and mountain zebra, allows for this increased investment. | ||||
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| Notes | from Professor Hans Klingels Equine Reference List | Approved | yes | ||
| Call Number | Serial | 1113 | |||
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| Author | Dugatkin, L.A. | ||||
| Title | Dynamics of the TIT FOR TAT strategy during predator inspection in the guppy (Poecilia reticulata) | Type | Journal Article | ||
| Year | 1991 | Publication | Behavioral Ecology and Sociobiology | Abbreviated Journal | Behav. Ecol. Sociobiol. |
| Volume | 29 | Issue | 2 | Pages | 127-132 |
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| Abstract | One well-known solution to the iterated Prisoner's Dilemma is the TIT FOR TAT strategy. This strategy has three “characteristics” associated with it. TIT FOR TAT is nice (cooperates on the first move of a game), retaliatory (plays defect against an individual that defected on the prior move), and forgiving (cooperates with an individual which has defected in the past but cooperates in the present). Predator inspection behavior in guppies (Poecilia reticulata) was examined in order to determine whether guppies displayed these three characteristics. Results indicate that while it can be quite difficult to translate the abstract concepts of niceness, retaliation, and forgiveness into measurable behaviors, the data support the hypothesis that guppies display the three characteristics associated with the TIT FOR TAT strategy. | ||||
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| Notes | Approved | no | |||
| Call Number | Equine Behaviour @ team @ | Serial | 2178 | ||
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| Author | Wittig, R.M.; Boesch, C. | ||||
| Title | “Decision-making” in conflicts of wild chimpanzees (Pan troglodytes): an extension of the Relational Model | Type | Journal Article | ||
| Year | 2003 | Publication | Behavioral Ecology and Sociobiology | Abbreviated Journal | Behav. Ecol. Sociobiol. |
| Volume | 54 | Issue | 5 | Pages | 491-504 |
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| Abstract | >We examined the “decision-making” process of aggressive interactions within a community of wild chimpanzees ( Pan troglodytes verus) in the Taï National Park, Côte d’Ivoire (West Africa). Costs and benefits were investigated for 876 dyadic aggressive interactions among 18 adults (including 4 independent adolescents) of either sex. An extended version of the Relational Model was developed to describe the dynamics of the “decision-making” process in Taï chimpanzees, which suggests that the net benefit determines the occurrence of conflicts. Both sexes fought more frequently for the resources that were most important to them, food for females and social contexts for males. Individuals used two different strategies according to their likelihood of winning the aggressive interaction, determined by the dominance relationship of the conflict partners. Dominant initiators had longer and more intense aggressive interactions, but they limited their social disadvantages by fighting non-cooperative partners. Subordinate initiators had shorter and less intense aggressive interactions, but risked more social costs, which they could reduce afterwards by reconciliation. Both strategies included a positive overall net benefit. The extended Relational Model fits the complexity of wild chimpanzee conflicts and allows for more flexibility in the “decision-making” compared to the original version. | ||||
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| Notes | Approved | no | |||
| Call Number | Equine Behaviour @ team @ | Serial | 2206 | ||
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| Author | Kirkpatrick, J.F.; Turner, J.W. | ||||
| Title | Changes in herd stallions among feral horse bands and the absence of forced copulation and induced abortion | Type | Journal Article | ||
| Year | 1991 | Publication | Behavioral Ecology and Sociobiology | Abbreviated Journal | Behav. Ecol. Sociobiol. |
| Volume | 29 | Issue | 3 | Pages | 217-219 |
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| Abstract | Forced copulation and induced abortion were investigated in a herd of feral horses inhabiting a coastal barrier island. Eight mares were diagnosed pregnant in August and October 1989 by means of urinary and fecal steroid metabolites, prior to documented changes in herd stallions. These mares were observed for harassment and forced copulation by the new stallions and for the presence of foals during the spring and summer of 1990. No incidents of harassment or attempts at forced copulation were witnessed and seven of the eight mares produced foals in 1990. These data indicate that forced copulation and induced abortion are not common events among all feral horse herds and suggest reinvestigation of this hypothesized phenomenon. | ||||
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| Call Number | Equine Behaviour @ team @ | Serial | 2327 | ||
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| Author | Monard, A.-M.; Duncan, P.; Fritz, H.; Feh, C. | ||||
| Title | Variations in the birth sex ratio and neonatal mortality in a natural herd of horses | Type | Journal Article | ||
| Year | 1997 | Publication | Behavioral Ecology and Sociobiology | Abbreviated Journal | Behav. Ecol. Sociobiol. |
| Volume | 41 | Issue | 4 | Pages | 243-249 |
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| Abstract | Variations in birth sex ratios and sex differences in juvenile mortality occur in a number of mammalian species, and in many cases have been linked to resource availability. Most of these biases in offspring sex ratios concern polygynous species with pronounced sexual dimorphism, and where females only are philopatric. Data on species with unusual life-history strategies, such as slight sexual dimorphism or dispersal by both sexes, are of particular interest. In this study of a natural herd of horses (Equus caballus) which experienced an eruptive cycle, and therefore a period of nutritional stress, male offspring had higher neonatal mortality rates in nutritionally poor years than in good ones, whereas “year quality” had no effect on the mortality of female offspring; year quality could therefore be used by mares as predictor of sex-specific offspring survival. We show that the environmental conditions that predicted lower survival of males were negatively related to their production: the birth sex ratio the following year was female-biased; and mares were less likely to produce a son when they had produced a son the preceding year. There was no significant effect of mother's parity, age or rank, or the timing of conception or birth on offspring sex ratios. The mechanism leading to biases in the birth sex ratio could have been the loss of male embryos by mares that did not foal. As there was no evidence for selective abortion of male foetuses in females that did foal the next year, it is not necessary to invoke maternal adjustment, though this remains a possibility. Finally, there was a suggestion that male offspring were more costly to raise than females, since mothers that reared a son in poor years tended to experience an increase in the interbirth interval between their two subsequent offspring. | ||||
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| Call Number | Equine Behaviour @ team @ | Serial | 2388 | ||
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| Author | Zuberbühler, K. | ||||
| Title | Predator-specific alarm calls in Campbell's monkeys, Cercopithecus campbelli | Type | Journal Article | ||
| Year | 2001 | Publication | Behavioral Ecology and Sociobiology | Abbreviated Journal | Behav. Ecol. Sociobiol. |
| Volume | 50 | Issue | 5 | Pages | 414-422 |
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| Abstract | One of the most prominent behavioural features of many forest primates are the loud calls given by the adult males. Early observational studies repeatedly postulated that these calls function in intragroup spacing or intergroup avoidance. More recent field experiments with Diana monkeys (Cercopithecus diana) of Taï Forest, Ivory Coast, have clearly shown that loud male calls function as predator alarm calls because calls reliably (1) label different predator classes and (2) convey semantic information about the predator type present. Here, I test the alarm call hypothesis another primate, the Campbell's monkey (C. campbelli). Like Diana monkeys, male Campbell's monkeys produce conspicuous loud calls to crowned hawk eagles (Stephanoaetus coronatus) and leopards (Panthera pardus), two of their main predators. Playback experiments showed that monkeys responded to the predator category represented by the different playback stimuli, regardless of whether they consisted of (1) vocalisations of the actual predators (crowned hawk eagle shrieks or leopard growls), (2) alarm calls to crowned hawk eagles or leopards given by other male Campbell's monkeys or (3) alarm calls to crowned hawk eagles or leopards given by sympatric male Diana monkeys. These experiments provide further evidence that non-human primates have evolved the cognitive capacity to produce and respond to referential labels for external events. | ||||
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| Notes | Approved | no | |||
| Call Number | Equine Behaviour @ team @ | Serial | 3116 | ||
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