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Roberts, J., Kacelnik, A., & Hunter, M. L. (1979). A model of sound interference in relation to acoustic communication. Anim. Behav., 27(Part 4), 1271–1273.
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Robins, A., & Rogers, L. J. (2004). Lateralized prey-catching responses in the cane toad, Bufo marinus: analysis of complex visual stimuli. Anim. Behav., 68(4), 767–775.
Abstract: We tested the responses of Bufo marinus to prey stimuli of varying visual complexity that were moved around the toads in either a clockwise or anticlockwise direction at 1.7 revolutions/min. Predatory responses directed at prey resembling an insect were frequent when the model insect moved clockwise across the visual midline into the right visual hemifield. In contrast, the toads tended to ignore such stimuli when they moved anticlockwise across the midline into the left hemifield. No such lateralization was found when a rectangular strip moved along its longest axis was presented in a similar way. The toads also directed more responses towards the latter stimulus than towards the insect prey. Hence, the results suggest that lateralized predatory responses occur for considered decisions on whether or not to respond to complex insect-like stimuli, but not for decisions on comparatively simple stimuli. We discuss similarities between the lateralized feeding responses of B. marinus and those of avian species, as support for the hypothesis that lateralized brain function in tetrapods may have arisen from a common lateralized ancestor.
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Rutberg, A. T. (1990). Inter-group transfer in assateague pony mares. Anim. Behav., 40(5), 945–952.
Abstract: Between-previous termgroup transfernext term of adult female previous termponies,next term Equus caballus, was investigated for three consecutive summers on previous Assateaguenext Island, Maryland, U.S.A. Both the previous terminternext term-band movements of individual previous termmares and the marenext term turnover rates of one-male “harem” bands were examined. Long-term previous termtransfersnext term occurred at rates ranging from 0·06 to 0·18 per previous termmarenext term per month. previous termMaresnext term with foals transferred more frequently than previous termmaresnext term without foals, but neither female age, pregnancy, nearest-neighbour distances nor dominance rank affected the likelihood of transferring. Band turnover rates were uncorrelated with the average frequency of previous termmare-marenext term aggression within the band, but new previous termmaresnext term entering a band suffered a transient rise in aggression received. Thus, female aggression did not encourage, and may have discouraged, previous terminternext term-band previous termtransfers.next term Older stallions and stallions who had held bands for 2 years or more had significantly larger and more stable bands. Fewer previous termmarenext term turnovers were seen in bands whose stallions tended to face their previous termmares,next term showed a relatively high proportion of time feeding, and showed a relatively low proportion of time involved in aggression with other stallions, although at marginal levels of significance for all three variables. Thus, variability in stallion attributes, and possibly behaviour, probably plays the strongest role in determining previous termmare transfernext term patterns at previous termAssateague.next term
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Rutberg, A. T., & Greenberg, S. A. (1990). Dominance, aggression frequencies and modes of aggressive competition in feral pony mares. Anim. Behav., 40(2), 322–331.
Abstract: Feral pony mares, Equus caballus, at Assateague Island, Maryland, formed linear dominance hierarchies within bands. Generally, older mares dominated younger mares, and larger mares dominated smaller mares. Large mares initiated aggression more often than small mares when age was controlled for but, surprisingly, older mares initiated aggression less often than younger mares when size was controlled for. Thus, mares peak in aggressiveness fairly soon after achieving full size and then, while maintaining or improving their rank in the domainance hierarchy, progressively reduce their involvement in aggression as they grow older, Involvement in aggression per mare increased as number of mares in the group increased; this effect was independent of nearest-mare distances. Frequency of involvement in aggression did not differ between mares that had changed bands within the year and mares whose band association had continued for a year or more. Aggression was directed more frequently than expected at subordinate mares who were nursing, and also occurred more frequently than expected at water holes. The proportion of aggressive encounters during grazing closely matched the total proportion of time spent grazing. Subordinate mares with foals received aggression more often than subordinate mares without foals. The high frequency of aggression associated with foals and nursing suggests that interference with reproduction of subordiantes is an important mode of competition between mares. Such interference may be common in animals that feed on dispersed resources and live in small, cohesive groups.
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Rutberg, A. T., & Keiper, R. R. (1993). Proximate causes of natal dispersal in feral ponies: some sex differences. Anim. Behav., 46(5), 969–975.
Abstract: Abstract. Fifteen years of data on natal dispersal age and the context of dispersal for the feral ponies of Assateague Island, Maryland are presented. Ninety-seven per cent of males and 81% of females dispersed from their natal groups by 5 years of age. For animals that left their natal group, average age of dispersal was 20[middle dot]8 months for males and 24[middle dot]6 months for females. Male dispersal age was strongly and significantly correlated with number of peers in the natal group, and males dispersing with peers were significantly older than males dispersing without peers, suggesting that males delayed dispersal when peers were available for interaction. Female dispersal age was not influenced by number of peers, but was correlated with age of first reproduction. Factors not influencing dispersal age in either sex were presence of a younger sibling, maternal band transfers, and maternal age and dominance rank. The relatively high frequency of females failing to disperse from their natal groups is puzzling in light of data showing diminished fecundity in non-dispersing pony mares.
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Sands, J., & Creel, S. (2004). Social dominance, aggression and faecal glucocorticoid levels in a wild population of wolves, Canis lupus. Anim. Behav., 67(3), 387–396.
Abstract: Adrenal glucocorticoid (GC) secretion is an important component of the response to stress in vertebrates. A short-term increase in circulating GCs serves to redirect energy from processes that can be briefly curtailed without harm, allowing energy to be directed towards eliminating or avoiding the stressor. In contrast, prolonged elevation of GCs can cause a broad range of pathologies, including reproductive suppression. We examined whether social subordination in wolves leads to chronically elevated GC levels, and whether this [`]social stress' causes reproductive suppression of subordinates in cooperatively breeding species. Behavioural and endocrine data collected over 2 years from three packs of free-living wolves in Yellowstone National Park did not support this hypothesis. GC levels were significantly higher in dominant wolves than in subordinates, for both sexes, in all packs, in both years of study. Unlike other cooperatively breeding carnivores (e.g. dwarf mongooses, Helogale parvula, and African wild dogs, Lycaon pictus), high GCs in dominant wolves were not associated with high rates of aggression or agonistic interaction. Aggression increased for wolves of all ranks during mating periods, accompanied by a significant rise in GC levels. If chronic elevation of GCs carries fitness costs, then social stress in wolves (and many other social species) is a cost of dominance, not a consequence of subordination. The specific behavioural correlates of dominance that affect GC levels appear to vary among species, even those with similar social systems.
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Sara J. Shettleworth. (1999). Female mate choice in swordtails and mollies: symmetry assessment or Weber's law? Anim. Behav., 58(5), 1139–1142.
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Sárová, R., Spinka, M., Panamá, J. L. A., & Simecek, P. (2010). Graded leadership by dominant animals in a herd of female beef cattle on pasture. Anim. Behav., 79(5), 1037–1045.
Abstract: The role of dominant individuals in leading groups of animals is not yet well understood. We investigated whether dominant beef cows, Bos taurus, have more influence on herd movement on pasture than more subordinate cows. A herd of 15 Gasconne cows was observed for a 3-week period between dawn and dusk. The positions of all adult cows were recorded with GPS collars at 1 min intervals and the behaviour of each cow was recorded in 5 min scans. The dominance hierarchy was recorded by ad libitum sampling. Through cluster analysis of the recorded data, we distinguished three herd behaviour patterns: resting, foraging and travelling. Dominant cows were closer to the front of the herd during both travelling and foraging. During travelling, more dominant cows also had more direct trajectories and were more aligned both with their nearest neighbours and with the whole herd. During foraging, the trajectories of dominant cows were shorter than those of subordinate cows. The results indicate that foraging and short-distance travelling movements by female beef cattle are not led by any particular individual but rather are influenced by a graded type of leadership; that is, the more dominant a cow is, the stronger the influence it may have on the movements of the herd.
Keywords: Bos taurus; cattle; dominance; foraging; Gps; group movement; leadership
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Sayigh, L. S., Tyack, P. L., Wells, R. S., Solow, A. R., Scott, M. D., & Irvine, A. B. (1999). Individual recognition in wild bottlenose dolphins: a field test using playback experiments. Anim. Behav., 57(1), 41–50.
Abstract: We conducted playback experiments with wild bottlenose dolphins, Tursiops truncatus, to determine whether there is sufficient information in their individually distinctive signature whistles for individual recognition. We conducted experiments with members of a resident community of dolphins in waters near Sarasota, Florida, during temporary capture-release projects. We used a paired playback design, wherein the same two whistle sequences were predicted to evoke opposite responses from two different target animals. This design controlled for any unknown cues that may have been present in the playback stimuli. We predicted that mothers would respond more strongly to the whistles of their own independent offspring than to the whistles of a familiar, similar-aged nonoffspring. Similarly, we predicted that independent offspring would respond more strongly to the whistles of their own mother than to the whistles of a familiar, similar-aged female. Target animals were significantly (P<0.02) more likely to respond to the predicted stimuli, with responses measured by the number of head turns towards the playback speaker. In bottlenose dolphin societies, stable, individual-specific relationships are intermixed with fluid patterns of association between individuals. In primate species that live in similar 'fission-fusion' type societies, individual recognition is commonplace. Thus, when taken in the context of what is known about the social structure and behaviour of bottlenose dolphins, these playback experiments suggest that signature whistles are used for individual recognition. Copyright 1999 The Association for the Study of Animal Behaviour.
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Schloegl, C., Kotrschal, K., & Bugnyar, T. (2007). Gaze following in common ravens, Corvus corax: ontogeny and habituation. Anim. Behav., 74(4), 769–778.
Abstract: Co-orientation with others by using their gaze direction is considered to be adaptive for detecting food or predators or monitoring social interactions. Like the great apes, common ravens are capable of following human experimenters' gaze direction not only into distant space but also behind visual barriers. We investigated the ontogenetic development of these abilities by confronting birds with a human foster parent looking up (experiment 1) and behind visual barriers (experiment 3) and their modification by habituation (experiments 2 and 4). We tested a group of 12 hand-reared ravens during their first 10 months of life. Ravens responded to others' look-ups soon after fledging but could track their gaze behind a visual barrier only 4 months later, at the age they usually become independent from their parents. Furthermore, ravens quickly ceased responding to repeated look-ups by the model, but did not habituate to repeated gaze cues directed behind a barrier. Our findings support the idea that the two modes of gaze following reflect different cognitive levels in ravens and, possibly, have different functions.
Keywords: Corvus corax; gaze following; habituation; ontogenetic development; raven
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