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Dellert, B., & Ganslosser, U. (1997). Experimental alterations of food distribution in two species of captive equids (Equus burchelli and E. hemionus kulan). Ethol Ecol Evol, 9(1), 1–17.
Abstract: n one group each of Plains zebra (six mares, one foal, one subadult) and Asiatic wild asses (seven mares, two foals) at Nuremberg Zoo, food distribution was experimentally changed from clumped (all food in one standard hay rack) to dispersed (one heap per animal). Both groups were characterized by different social structures, which basically remained during the experiment. Plains zebras had an individually structured system of social relationships in a dominance order, wild asses a more egalitarian system without clear-cut rank differences and low frequencies of agonistic interactions. Access to food accordingly was individually (but consistently) different for zebra mares, almost equal for wild ass mares. During the dispersed feeding situation frequencies of agonistic interactions in both species decreased (however non-significantly), individual distances increased but mares also frequently ''visited'' each others' heaps. Feeding time increased for all wild ass mares. Some individuals (in both groups) behaved ''against the trend'' in agonistic behaviour. The results are discussed with regard to food distribution for ungulates in general, and equid social systems.
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Dall, S. R. X., Giraldeau, L. - A., Olsson, O., McNamara, J. M., & Stephens, D. W. (2005). Information and its use by animals in evolutionary ecology. Trends Ecol Evol, 20(4), 187–193.
Abstract: Information is a crucial currency for animals from both a behavioural and evolutionary perspective. Adaptive behaviour relies upon accurate estimation of relevant ecological parameters; the better informed an individual, the better it can develop and adjust its behaviour to meet the demands of a variable world. Here, we focus on the burgeoning interest in the impact of ecological uncertainty on adaptation, and the means by which it can be reduced by gathering information, from both 'passive' and 'responsive' sources. Our overview demonstrates the value of adopting an explicitly informational approach, and highlights the components that one needs to develop useful approaches to studying information use by animals. We propose a quantitative framework, based on statistical decision theory, for analysing animal information use in evolutionary ecology. Our purpose is to promote an integrative approach to studying information use by animals, which is itself integral to adaptive animal behaviour and organismal biology.
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Czaran, T. (1999). Game theory and evolutionary ecology: Evolutionary Games & Population Dynamics by J. Hofbauer and K. Sigmund, and Game Theory & Animal Behaviour, edited by L.A. Dugatkin and H.K. Reeve. Trends. Ecol. Evol, 14(6), 246–247.
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Creel, S. (2001). Social dominance and stress hormones. Trends. Ecol. Evol, 16(9), 491–497.
Abstract: In most cooperatively breeding birds and mammals, reproductive rates are lower for social subordinates than for dominants, and it is common for reproduction in subordinates to be completely suppressed. Early research conducted in captivity showed that losing fights can increase glucocorticoid (GC) secretion, a general response to stress. Because GCs can suppress reproduction, it has been widely argued that chronic stress might underlie reproductive suppression of social subordinates in cooperative breeders. Contradicting this hypothesis, recent studies of cooperative breeders in the wild show that dominant individuals have elevated GCs more often than do subordinates. The findings that elevated GCs can be a consequence of subordination or a cost of dominance complicate the conventional view of social stress, with broad ramifications for the evolution of dominance and reproductive suppression.
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Cozzi, B., Povinelli, M., Ballarin, C., & Granato, A. (2014). The Brain of the Horse: Weight and Cephalization Quotients. Brain Behav Evol, 83(1), 9–16.
Abstract: The horse is a common domestic animal whose anatomy has been studied since the XVI century. However, a modern neuroanatomy of this species does not exist and most of the data utilized in textbooks and reviews derive from single specimens or relatively old literature. Here, we report information on the brain of Equus caballus obtained by sampling 131 horses, including brain weight (as a whole and subdivided into its constituents), encephalization quotient (EQ), and cerebellar quotient (CQ), and comparisons with what is known about other relevant species. The mean weight of the fresh brains in our experimental series was 598.63 g (SEM ± 7.65), with a mean body weight of 514.12 kg (SEM ± 15.42). The EQ was 0.78 and the CQ was 0.841. The data we obtained indicate that the horse possesses a large, convoluted brain, with a weight similar to that of other hoofed species of like mass. However, the shape of the brain, the noteworthy folding of the neocortex, and the peculiar longitudinal distribution of the gyri suggest an evolutionary specificity at least partially separate from that of the Cetartiodactyla (even-toed mammals and cetaceans) with whom Perissodactyla (odd-toed mammals) are often grouped.
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Conradt, L., & Roper, T. J. (2005). Consensus decision making in animals. Trends Ecol Evol, 20(8), 449–456.
Abstract: Individual animals routinely face decisions that are crucial to their fitness. In social species, however, many of these decisions need to be made jointly with other group members because the group will split apart unless a consensus is reached. Here, we review empirical and theoretical studies of consensus decision making, and place them in a coherent framework. In particular, we classify consensus decisions according to the degree to which they involve conflict of interest between group members, and whether they involve either local or global communication; we ask, for different categories of consensus decision, who makes the decision, what are the underlying mechanisms, and what are the functional consequences. We conclude that consensus decision making is common in non-human animals, and that cooperation between group members in the decision-making process is likely to be the norm, even when the decision involves significant conflict of interest.
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Connor, R. C., Mann, J., Tyack, P. L., & Whitehead, H. (1998). Social evolution in toothed whales. Trends. Ecol. Evol, 13(6), 228–232.
Abstract: Two contrasting results emerge from comparisons of the social systems of several odontocetes with terrestrial mammals. Researchers have identified remarkable convergence in prominent features of the social systems of odontocetes such as the sperm whale and bottlenose dolphin with a few well-known terrestrial mammals such as the elephant and chimpanzee. In contrast, studies on killer whales and Baird's beaked whale reveal novel social solutions to aquatic living. The combination of convergent and novel features in odontocete social systems promise a more general understanding of the ecological determinants of social systems in both terrestrial and aquatic habitats, as well as the relationship between relative brain size and social evolution.
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Connor, R. C. (1995). Altruism among non-relatives: alternatives to the 'Prisoner's Dilemma'. Trends Ecol Evol, 10(2), 84–86.
Abstract: Triver's model of reciprocal altruism, and its descendants based on the Prisoner's Dilemma model, have dominated thinking about cooperation and altruism between non-relatives. However, there are three alternative models of altruism directed to non-relatives. These models, which are not based on the Prisoner's Dilemma, may explain a variety of phenomena, from allogrooming among impala to helping by non-relatives in cooperatively breeding birds and mammals.
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Clutton-Brock, J. (1995). Origins of the dog: domestication and early history. In J. A. Serpell (Ed.), The Domestic Dog: Its Evolution, Behaviour and Interactions with People. Cambridge: Cambridge University Press.
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Chance, M. R. A., & Mead, A. P. (1953). Social behaviour and primate evolution. Symposia of the Society for Experimental Biology,. Evolution, 7, 395–439.
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