Kimura, R. (1998). Mutual grooming and preferred associate relationships in a band of free-ranging horses. Appl. Anim. Behav. Sci., 59(4), 265–276.
Abstract: Preferred associate (nearest neighbour) and mutual grooming relationships among mares, in an isolated family band of free-ranging horses (Equus caballus), were studied, and the structural and functional differences between these two relationships were examined. The frequent partners accompanying the mare were not the same in both these relationships (p<0.05) and mares changed their partners during the study period between 1988-1990. Individual horses of similar rank tended to remain closer together in both winter and summer. Aggressive-submissive behaviour was so infrequent during spring that rank determinations could not be made; however, in fall, although rank could be determined, rank was not correlated with nearest neighbour. Three subgroups, based on preferred associate relationships in summer, fall and winter, directly reflected the age and social rank of the mares in the group. Individual horses of higher rank tended to have many partners in winter, while individuals of lower rank had fewer. There was no significant correlation between the frequency of mutual grooming and individual rank. The mutual grooming relationship was strongly influenced by seasonal changes as the relative amount of grazing time per day increased. Thus, the frequency of mutual grooming was lowest in winter and highest in summer. The mutual grooming relationship was based on the bonds between individual horses, which were little influenced by social rank. Lower ranking individuals tended to have a greater variety of grooming partners in summer.
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Coleman, K., & Wilson, D. S. (1998). Shyness and boldness in pumpkinseed sunfish: individual differences are context-specific. Anim. Behav., 56(4), 927–936.
Abstract: Natural selection often promotes a mix of behavioural phenotypes in a population. Adaptive variation in the propensity to take risks might explain individual differences in shyness and boldness in humans and other species. It is often implicitly assumed that shyness and boldness are general personality traits expressed across many situations. From the evolutionary standpoint, however, individual differences that are adaptive in one context (e.g. predator defence) may not be adaptive in other contexts (e.g. exploration of the physical environment or intraspecific social interactions). We measured the context specificity of shyness and boldness in a natural population of juvenile pumpkinseed sunfish,Lepomis gibbosus, by exposing the fish to a potentially threatening stimulus (a red-tipped metrestick extended towards the individual) and a nonthreatening stimulus (a novel food source). We also related these measures of shyness and boldness to behaviours observed during focal observations, both before and after the introduction of a predator (largemouth bass,Micropterus salmoides). Consistent individual differences were found within both contexts, but individual differences did not correlate across contexts. Furthermore, fish that were scored as intermediate in their response to the metrestick behaved most boldly as foragers and in response to the bass predators. These results suggest that shyness and boldness are context-specific and may not exist as a one-dimensional behavioural continuum even within a single context.
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Oliveira, R. F., McGregor, P. K., & Latruffe, C. (1998). Know thine enemy: fighting fish gather information from observing conspecific interactions. Proc. Roy. Soc. Lond. B Biol. Sci., 265(1401), 1045–1049.
Abstract: Many of the signals that animals use to communicate transmit relatively large distances and therefore encompass several potential signallers and receivers. This observation challenges the common characterization of animal communication systems as consisting of one signaller and one receiver. Furthermore, it suggests that the evolution of communication behaviour must be considered as occurring in the context of communication networks rather than dyads. Although considerations of selection pressures acting upon signallers in the context of communication networks have rarely been expressed in such terms, it has been noted that many signals exchanged during aggressive interactions will transmit far further than required for information transfer between the individuals directly involved, suggesting that these signals have been designed to be received by other, more distant, individuals. Here we consider the potential for receivers in communication networks to gather information, one aspect of which has been termed eavesdropping. We show that male Betta splendens monitor aggressive interactions between neighbouring conspecifics and use the information on relative fighting ability in subsequent aggressive interactions with the males they have observed.
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Scheibe, K. M., Schleusner, T., Berger, A., Eichhorn, K., Langbein, J., Dal Zotto, L., et al. (1998). ETHOSYS (R)--new system for recording and analysis of behaviour of free-ranging domestic animals and wildlife. Appl. Anim. Behav. Sci., 55(3-4), 195–211.
Abstract: A storage telemetry system has been developed to monitor domestic animals and wildlife, and has been tested under variable conditions on sheep, Przewalski horse and mouflon. It can be used for automatic recording of different patterns of behaviour, such as activity and feeding, and is based on advanced analysis of sensor-emitted signals. The system is made up of collars (ETHOREC) with sensors and electronic devices for behaviour recording, a central station (ETHOLINK) and software for data transmission and processing (ETHODAT). All components of the ETHOREC recording device are integrated in the collar. Long-time recording of behaviour through up to four different channels and in numerous animals at one and the same time are necessary elements to facilitate biorhythmic analysis of animals under free-ranging conditions. The results obtained from this telemetry system were compared with visual observations on six sheep and four Przewalski horses. Parallel recordings were taken from four sheep, using a recorder for jaw movements. Locomotor activity usually was rated somewhat higher by observers, whereas feed uptake was rated lower. Higher feed uptake values were measured by means of the jaw movement recorder, although deviations thus measured varied less than those noticed by visual observations. All measured series exhibited significant correlations with control values. The system, consequently, was found to be more suitable for determination of diurnal patterns, change over time and relative comparison between behaviour levels than it actually was for measurement of absolute duration of a given behaviour.
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Blunden, A. S., Smith, K. C., Whitwell, K. E., & Dunn, K. A. (1998). Systemic infection by equid herpesvirus-1 in a Grevy's zebra stallion (Equus grevyi) with particular reference to genital pathology. J Comp Pathol, 119(4), 485–493.
Abstract: A severe multi-systemic form of equid herpesvirus-1 infection is described in an adult zebra stallion. There was multifocal necrotizing rhinitis, marked hydrothorax and pulmonary oedema, with viral antigen expression in degenerating epithelial cells, local endothelial cells and intravascular leucocytes of the nasal mucosa and lung. Specific localization of EHV-1 infection was seen in the testes and epididymides, including infection of Leydig cells and germinal epithelium, which would have facilitated venereal shedding of virus in life. The case provided a unique opportunity to study hitherto undescribed aspects of the pathogenesis of naturally occurring EHV-1 infection in the male equine genital tract. Restriction digests of the isolate demonstrated a pattern similar to that of EHV-1 isolates previously recovered from aborted zebra and onager fetuses.
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Bouman, I. (1998). The reintroduction of Przewalski horses in the Hustain Nuruu Mountain Forest Steppe Reserve in Mongolia. Mededelingen: Netherlands Commission for International Nature Protection, 32.
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Boyd, L. (1998). The 24-h time budget of a takh harem stallion (Equus ferus przewalskii) pre- and post-reintroduction. Appl. Anim. Behav. Sci., 60(4), 291–299.
Abstract: Focal animal sampling was used to determine the 24-h time budget of a takh harem stallion (Equus ferus przewalskii) during the 2 weeks prior to, and the two weeks following, reintroduction into the Hustain Nuruu Steppe Reserve, Mongolia. Both before and after release, the stallion spent approximately 47% of his time grazing, 6% standing, and 5% in recumbent rest. The biggest changes to the time budget after release were a 4-fold increase in the amount of time spent moving, and a 50% decrease in the amount of time spent resting in a standing position. During the middle of the day when the temperatures were hottest, the stallion exhibited less grazing and more standing resting behaviour than in the morning or evening hours. Recumbent rest invariably occurred in the hours before dawn.
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Moehlman, P. D., Kebede, F., & Yohannes, H. (1998). The African wild ass (Equus africanus): conservation status in the horn of Africa. Appl. Anim. Behav. Sci., 60(2-3), 115–124.
Abstract: From 1989 to 1996, surveys were made in most of the historic range of African wild asses in Somalia, Ethiopia, and Eritrea. From the 1970s to the mid 1990s populations of African wild asses (Equus africanus, Fitzinger, 1857) in Somalia and Ethiopia have declined from approximately 6 to 30 per 100 km2 to 1 or 2 per 100 km2. Given the current IUCN criteria, they are Critically Endangered (CR) and face extremely high risk of extinction in the wild in the immediate future, as their populations have been reduced by at least 80% over the last 10+ years (IUCN, 1994). Basic research is needed on this species as scientific information on its reproductive biology, behavior, ecology, and genetics is very limited. Improved support needs to be provided to existing parks and reserves and new multiple use reserves need to be established.
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Moehlman, P. D. (1998). Behavioral patterns and communication in feral asses (Equus africanus). Appl. Anim. Behav. Sci., 60(2-3), 125–169.
Abstract: The behavior of feral populations of the African wild ass (Equus africanus) were studied in the Northern Panamint Range of Death Valley National Monument for 20 months from 1970 to 1973 [Moehlman, P.D., 1974. Behavior and ecology of feral asses (Equus asinus). PhD dissertation, University of Wisconsin, Madison, 251 pp.; Moehlman, P.D., 1979. Behavior and ecology of feral asses (Equus asinus). Natl. Geogr. Soc. Res. Reports, 1970: 405-411]. Maintenance behavior is described and behavior sequences that were used in social interactions are quantified by sex and age class. Agonistic, sexual, and greeting behavior patterns are described and analyzed in conjunction with the responses they elicited. Mutual grooming mainly occurred between adult males, and between females and their offspring. Five types of vocalizations were distinguished: brays, grunts, growls, snorts, and whuffles. A second population was studied for 1 month on Ossabaw Island, GA (Moehlman, 1979). This population had more permanent social groups and had a higher rate of mutual grooming and foal social play.
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Moehlman, P. D. (1998). Feral asses (Equus africanus): intraspecific variation in social organization in arid and mesic habitats. Appl. Anim. Behav. Sci., 60(2-3), 171–195.
Abstract: Feral asses have been studied in the arid habitats of the southwestern United States [Moehlman, P.D., 1974. Behavior and ecology of feral asses (Equus asinus). PhD dissertation, University of Wisconsin, Madison, 251 pp.; Moehlman, P.D., 1979. Behavior and ecology of feral asses (Equus asinus). Nat. Geogr. Soc. Res. Reports 1970, 405-411.; Woodward, S.L., 1979. The social system of feral asses (Equus asinus). Z. Tierpsychol. 49, 304-316] and in the mesic habitat of Ossabaw Island, Georgia [Moehlman, P.D., 1979, ibid; McCort, W.D., 1980. The feral asses (Equus asinus) of Ossabaw Island, Georgia. PhD dissertation, Pennsylvania State University, University Park, 219 pp]. The feral ass populations in these two locales exhibited intraspecific variation in polygynous mating systems and social organization which were consistent with the ecological classification of mating systems of Emlen and Oring (1977) [Emlen, S.T., Oring, S.W., 1977. Ecology, sexual selection, and the evolution of mating systems. Science 197 (4300), 215-223]. Feral asses in the arid environment have a `resource defense' polygynous mating system, and those in the mesic habitat exhibit `female (harem) defense' polygyny. The intraspecific variation observed in feral asses encompasses the interspecific variation observed in the family Equidae.
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