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Lamprecht, J. (1992). Variable Leadership in Bar-Headed Geese (Anser Indicus) : an Analysis of Pair and Family Departures. Behaviour, 122(1-2), 105–119.
Abstract: This paper reports quantitative leadership differences in semi-captive bar-headed geese (Anser indicus) at different times of the year, and in different types of groups. Leading is defined here as causing the departure or determining the direction of movement of the whole group. No permanent and exclusive leader of a pair or family group was found, rather relative leading frequencies of male, female and young showed a definite shifting pattern. Females led more often than their mates prior to breeding, and on nest pauses during the incubation period, but less often in summer, autumn and early winter. In families there was no difference between the frequencies of male and female leading. Family females led relatively more often than those of pairs without offspring. This difference was related to the presence, not the number, of young. Goslings led the family about as often as the parents during the rearing period in early summer, less often in autumn, winter and next spring. Such differences and changes are to be expected where competence in particular tasks and dependence on partners vary between group members, and where different situations require different abilities. For the geese, the results can be related to the different options of group members and to the different benefits they derive from leaving (or 'staying put') or following (or waiting for the others) in different situations.
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Munthali, S. M., & Banda, H. M. (1992). Distribution and abundance of the common ungulates of Nyika National Park. Afr. J. Ecol, 30, 203–212.
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Dugatkin, L. A., & Godin, J. G. (1992). Reversal of female mate choice by copying in the guppy (Poecilia reticulata). Proc Biol Sci, 249(1325), 179–184.
Abstract: Ever since Fisher (1958) formalized models of sexual selection, female mate choice has been assumed to be a genetically determined trait. Females, however, may also use social cues to select mates. One such cue might be the mate choice of conspecifics. Here we report the first direct evidence that a female's preference for a particular male can in fact be reversed by social cues. In our experiments using the Trinidadian guppy (Poecilia reticulata), this reversal was mediated by mate-copying opportunities, such that a female (the 'focal' female) is given the opportunity to choose between two males, followed by a period in which she observes a second female (the 'model' female) displaying a preference for the male she herself did not prefer initially. When allowed to choose between the same males a second time, compared with control tests, a significant proportion of focal females reversed their mate choice and copied the preference of the model female. These results provide strong evidence for the role of non-genetic factors in sexual selection and underlie the need for new models of sexual selection that explicitly incorporate both genetic and cultural aspects of mate choice.
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Novacek, M. J. (1992). Mammalian phylogeny: shaking the tree. Nature, 356(6365), 121–125.
Abstract: Recent palaeontological discoveries and the correspondence between molecular and morphological results provide fresh insight on the deep structure of mammalian phylogeny. This new wave of research, however, has yet to resolve some important issues.
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Rubenstein, D. I., & Hack, M. A. (1992). Horse signals: The sounds and scents of fury. Evol. Ecol., 6(3), 254–260.
Abstract: During contests animals typically exchange information about fighting ability. Among feral horses these signals involve olfactory or acoustical elements and each type can effectively terminate contests before physical contact becomes necessary. Dung transplant experiments show that for stallions, irrespective of rank, olfactory signals such as dung sniffing encode information about familiarity suggesting that such signals can be used as signatures. As such they can provide indirect information about fighting ability as long as opponents associate identity with past performance. Play-back experiments, however, show that vocalizations, such as squeals, directly provide information about status regardless of stallion familiarity. Sonographs reveal that squeals of dominants are longer than those of subordinates and that only those of dominants have at their onset high-frequency components.
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Dugatkin, L. A., & Godin, G. J. (1992). Predator inspection, shoaling and foraging under predation hazard in the Trinidadian guppy,Poecilia reticulata. Environmental Biology of Fishes, 34(3), 265–276.
Abstract: Guppies,Poecilia reticulata, living in stream pools in Trinidad, West Indies, approached a potential fish predator (a cichlid fish model) in a tentative, saltatory manner, mainly as singletons or in pairs. Such behavior is referred to as predator inspection behavior. Inspectors approached the trunk and tail of the predator model more frequently, more closely and in larger groups than they approached the predator's head, which is presumably the most dangerous area around the predator. However, guppies were not observed in significantly larger shoals in the stream when the predator model was present. In a stream enclosure, guppies inspected the predator model more frequently when it was stationary compared to when it was moving, and made closer inspections to the posterior regions of the predator than to its head. Therefore, the guppies apparently regarded the predator model as a potential threat and modified their behavior accordingly when inspecting it. Guppies exhibited a lower feeding rate in the presence of the predator, suggesting a trade-off between foraging gains and safety against predation. Our results further suggest that predator inspection behavior may account for some of this reduction in foraging. These findings are discussed in the context of the benefits and costs of predator inspection behavior.
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Duncan P,. (1992). Zebras, asses, and horses. Broadview, Illinois: Kelvyn Press.
Abstract: Provides summaries of the conservation status, biology, and ecology of wild zebras, asses, and horses. The Action Plan presents chapters on taxonomy, genetics, reproductive biology, population dynamics, management, disease and epidemiology, and the importance of developing an assessment methodology that considers the role of equids in ecosystems.
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Winkler A,. (1992). The feeding ecology of the Cape Mountain zebra in the Mountain Zebra National Park. Doctoral thesis, , .
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Leng, V. (1992). Das Vielseitigkeitspferd. Der Vielseitigkeitsreiter. Ausbildung, Training, Event. München: Blv Verlagsgesellschaft.
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de Waal, F. B. M. (1992). Coalitions as part of reciprocal relations in the Arnhem chimpanzee colony. In A. H. Harcourt, & F. B. M. de Waal (Eds.), Coalitions and Alliances in Humans and Other Animals (pp. 233–257). Oxford: Oxford University Press.
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