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Berger, A.; Scheibe, K.-M.; Eichhorn, K.; Scheibe, A.; Streich, J. | ||||
| Title | Diurnal and ultradian rhythms of behaviour in a mare group of Przewalski horse (Equus ferus przewalskii), measured through one year under semi-reserve conditions | Type | Journal Article | ||
| Year | 1999 | Publication | Applied Animal Behaviour Science | Abbreviated Journal | Appl. Anim. Behav. Sci. |
| Volume | 64 | Issue | 1 | Pages | 1-17 |
| Keywords | Horse; Przewalski horse; Circadian rhythm; Ultradian rhythm; Feeding and nutrition; Telemetry; Stress | ||||
| Abstract | Investigations were conducted on four horses from a group of 12 Przewalski mares raised in different zoos and kept in a 44-ha enclosure under semi-natural conditions. Activity and feeding were continuously measured every second and were saved every 15 min by the storage-telemetry system ETHOSYS, from June 1995 to July 1996. Body mass of the horses was regularly recorded. Daily and monthly mean values, power spectra and DFC (as a measure for stability of rhythms synchronised with circadiurnal period) for activity and feeding were calculated. The general pattern of activity and feeding over the year was closely related to sunrise and sunset. Feeding accounted for 40% of total activity in summer and 62% in spring (all-year average being 52%). The level of activity was lowest in winter; whereas feeding was lowest in summer. The time budget for feeding reflected both feeding conditions and the annual pattern of body condition. Greatest activity occurred during daylight hours. Only on hot summer days, activity at night was higher than during daylight hours. Spectral analysis of activity and feeding in Przewalski horse showed a time pattern which was characterised by 24-h rhythmicity, but also by ultradian components with period lengths between 4.8 and 12 h, i.e., an activity pattern of up to five strong bouts per day. Annual variation in the pattern of power spectra was not high during the year. Results are discussed in connection with horse feeding strategy. Analysing the time structure of long-term and continuously measured activity and feeding could be a useful method to follow the general living conditions, especially the nutritional situation and to detect stressful conditions. | ||||
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| Notes | Approved | no | |||
| Call Number | Equine Behaviour @ team @ | Serial | 2236 | ||
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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 |
Berger, J.; Rudman, R. | ||||
| Title | Predation and Interactions between Coyotes and Feral Horse Foals | Type | Journal Article | ||
| Year | 1985 | Publication | ournal of Mammalogy | Abbreviated Journal | J. Mammal. |
| Volume | 66 | Issue | 2 | Pages | 401-402 |
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| Notes | Approved | no | |||
| Call Number | Serial | 2017 | |||
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| Author |
Bergstrom, C.T.; Lachmann, M. | ||||
| Title | Signaling among relatives. III. Talk is cheap | Type | Journal Article | ||
| Year | 1998 | Publication | Proceedings of the National Academy of Sciences of the United States of America | Abbreviated Journal | Proc. Natl. Acad. Sci. U.S.A. |
| Volume | 95 | Issue | 9 | Pages | 5100-5105 |
| Keywords | Animal Communication; Animals; Costs and Cost Analysis; *Evolution; Interpersonal Relations; Models, Biological | ||||
| Abstract | The Sir Philip Sidney game has been used by numerous authors to show how signal cost can facilitate honest signaling among relatives. Here, we demonstrate that, in this game, honest cost-free signals are possible as well, under very general conditions. Moreover, these cost-free signals are better for all participants than the previously explored alternatives. Recent empirical evidence suggests that begging is energetically inexpensive for nestling birds; this finding led some researchers to question the applicability of the costly signaling framework to nestling begging. Our results show that cost-free or inexpensive signals, as observed empirically, fall within the framework of signaling theory. | ||||
| Address | Department of Biological Sciences, Stanford University, Stanford, CA 94305, USA. carl@charles.stanford.edu | ||||
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| Language | English | Summary Language | Original Title | ||
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| ISSN | 0027-8424 | ISBN | Medium | ||
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| Notes | PMID:9560235 | Approved | no | ||
| Call Number | refbase @ user @ | Serial | 561 | ||
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| Author |
Bergstrom,C. T.; Lachmann, M. | ||||
| Title | Signalling among relatives. I. Is costly signalling too costly? | Type | Journal Article | ||
| Year | 1997 | Publication | Proceedings of the National Academy of Sciences of the United States of America | Abbreviated Journal | Proc. Natl. Acad. Sci. U.S.A. |
| Volume | 352(1353) | Issue | Pages | 609-617 | |
| Keywords | Signalling | ||||
| Abstract | ahavi's handicap principle,originally proposed as an explanation for sexual selection ofelaborate male traits, suggests that a sufficient cost to dishonest signals can outweigh the rewards of deception and allow individuals to communicate honestly. Maynard Smith (1991) and Johnstone and Grafen (1992) introduce the Sir Philip Sidney game in order to extend the handicap principle to interactions among related individuals, and to demonstrate that stable costly signalling systems can exist among relatives. In this paper we demonstrate that despite the benefits associated with honest information transfer, the costs incurred in a stable costly signalling system may leave all participants worse off than they would be in a system with no signalling at all. In both the discrete and continuous forms of the Sir Philip Sidney game, there exist conditions under which costly signalling among relatives, while stable, is so costly that it is disadvantageous compared with no signalling at all. We determine the factors which dictate signal cost and signal benefit in a generalized version of this game, and explain how signal cost can exceed signal value. Such results raise concerns about theevolutionary pathways which could have led to the existence of signalling equilibria in nature. The paper stresses the importance of comparing signalling equilibria with other possible strategies, beforedrawing conclusions regarding the optimality of signalling. |
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| Notes | Approved | no | |||
| Call Number | refbase @ user @ | Serial | 559 | ||
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| Author |
Bernstein, I. S. | ||||
| Title | Dominance, aggression and reproduction in primate societies | Type | Journal Article | ||
| Year | 1976 | Publication | Journal of Theoretical Biology | Abbreviated Journal | J. Theor. Biol. |
| Volume | 60 | Issue | 2 | Pages | 459-472 |
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| Abstract | Dominance relationships in primate societies are generally inferred by analyses of agonistic interactions. This aspect of social organization is so striking in macaque and baboon societies that many theoreticians have postulated selective mechanisms operating on the genetic attributes which contribute to high dominance rank. Alpha males were hypothesized to increase their genetic fitness by successfully competing with other males for access to ovulating females. Evidence relevant to these speculations has been mixed. Whereas some investigators found alpha males had near exclusive sexual access to females, others failed to confirm preferential access to ovulating females. Indeed, considerable variability in competition for females existed not only among species, but also among troops of the same species living in different habitats. Further, partner selection was not an exclusive male prerogative; females proved to express active preferences for particular males as sexual partners, and these preferences were not related to high male aggressivity. Alpha males, however, were noted to maintain their positions through social skills as members of a central core or alliance, and high rank was related primarily to seniority. Moreover, alpha males responded actively to challenges to the troop and were judged to contribute significantly to the survival of infants. It was therefore hypothesized that increased genetic fitness related to the increased survival of immature animals in the troop, most of which would already be the offspring of senior (and hence alpha) males. Selection would then be for the social skills leading to successful alliances in troop defense. Such skills might also relate to female partner preferences thus increasing the reproductive effectiveness of alpha males at any point in their careers, including years prior to and following their assumption of alpha rank. | ||||
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| ISSN | 0022-5193 | ISBN | Medium | ||
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| Notes | Approved | no | |||
| Call Number | Equine Behaviour @ team @ | Serial | 5441 | ||
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| Author |
Berry, M.P.S | ||||
| Title | A comparison of different wildlife production enterprises in the northern Cape Province, South Africa | Type | Journal Article | ||
| Year | 1986 | Publication | Abbreviated Journal | S. Afr. J. Wildl. Res. | |
| Volume | 16 | Issue | 4 | Pages | 124-128 |
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| Call Number | Equine Behaviour @ team @ | Serial | 2238 | ||
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| Author |
Biegler, R.; McGregor, A.; Krebs, J.R.; Healy, S.D. | ||||
| Title | A larger hippocampus is associated with longer-lasting spatial memory | Type | Journal Article | ||
| Year | 2001 | Publication | Proceedings of the National Academy of Sciences of the United States of America | Abbreviated Journal | Proc. Natl. Acad. Sci. U.S.A. |
| Volume | 98 | Issue | 12 | Pages | 6941-6944 |
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| Abstract | Volumetric studies in a range of animals (London taxi-drivers, polygynous male voles, nest-parasitic female cowbirds, and a number of food-storing birds) have shown that the size of the hippocampus, a brain region essential to learning and memory, is correlated with tasks involving an extra demand for spatial learning and memory. In this paper, we report the quantitative advantage that food storers gain from such an enlargement. Coal tits () a food-storing species, performed better than great tits (), a nonstoring species, on a task that assessed memory persistence but not on a task that assessed memory resolution or on one that tested memory capacity. These results show that the advantage to the food-storing species associated with an enlarged hippocampus is one of memory persistence. | ||||
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| Notes | 10.1073/pnas.121034798 | Approved | no | ||
| Call Number | Equine Behaviour @ team @ | Serial | 4743 | ||
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| Author |
Bingman V.P.; Able K.P. | ||||
| Title | Maps in birds: representational mechanisms and neural bases | Type | Journal Article | ||
| Year | 2002 | Publication | Current Opinion in Neurobiology | Abbreviated Journal | Curr. Opin. Neurobiol. |
| Volume | 12 | Issue | Pages | 745-750 | |
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| Call Number | refbase @ user @ | Serial | 3503 | ||
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| Author |
Birke, L.; Hockenhull, J.; Creighton, E.; Pinno, L.; Mee, J.; Mills, D. | ||||
| Title | Horses' responses to variation in human approach | Type | Journal Article | ||
| Year | Publication | Applied Animal Behaviour Science | Abbreviated Journal | Appl. Anim. Behav. Sci. | |
| Volume | In Press, Corrected Proof | Issue | Pages | ||
| Keywords | Horse; Flight response; Human approach; Body posture; Approach speed; Natural horsemanship | ||||
| Abstract | The behaviour of humans around horses is thought to have a substantial impact on how people are perceived in subsequent interactions and many horse trainers give detailed advice on how handlers should behave when initially approaching a loose horse. Here we report on three studies designed to explore the effect of different human approach styles on the behaviour of naïve and experienced horses. In the first study, the change in flight distance (distance at which horses started to avoid an approaching human) of twelve semi-feral Dartmoor ponies, undergoing training to allow handling, was assessed. Over the 10 handling sessions median flight distance decreased significantly (p < 0.001) from 2.38 m to 0.00 m and there was a significant positive shift in the ponies' behaviour following the appearance of the researcher (p = 0.002). In a second study the effect of a direct (vigorous, swinging a lead rope and with eye contact) versus indirect (relaxed, no rope swinging and without eye contact) approach style was assessed on six adult experienced riding horses. The mean flight distance during a direct approach style (6.87 m) was significantly greater than that which occurred during an indirect approach style (2.32 m). Direction of approach was not found to significantly affect flight distance. In a third study, the effect of the rope was removed and a similar method to the second study applied to a group of naïve, feral ponies. The effect of different components of approach style, speed of approach, handler body posture and direction of gaze, which might contribute to observed differences in behavioural responses, were then examined systematically in this population. This revealed no significant difference in mean flight distance between the two approach styles (2.28 m indirect versus 2.37 m direct approach), but ponies were significantly more likely to move off in trot (p = 0.025) and to travel further (p = 0.001) when a direct approach was used. Speed of approach was the most salient factor, with a fast approach increasing both the tendency to move off in trot (p < 0.001) and distance travelled (p < 0.001). Body posture (relaxed or tense) had no effect, while flight distance was significantly greater when the person was looking away (p = 0.045). These results suggest horses may have an important egocentric spatial barrier, which perhaps relates to personal space and triggering of the flight response. Contrary to popular belief, body posture did not appear to be very important in the contexts examined unless accompanied by extraneous aids, while the speed of approach is particularly significant. These results are of important practical relevance in reducing the risk of injury, and the effective management of horses with minimal stress. | ||||
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| ISSN | 0168-1591 | ISBN | Medium | ||
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| Notes | Approved | no | |||
| Call Number | Equine Behaviour @ team @ | Serial | 5401 | ||
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