| Home | [1–10] << 11 12 13 14 15 16 17 18 19 20 >> [21–30] |
|
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
|
|
Sarova, R., Spinka, M., & Panama, J. L. A. (2007). Synchronization and leadership in switches between resting and activity in a beef cattle herd--A case study. Appl. Anim. Behav. Sci., 108(3-4), 327–331.
Abstract: The mechanisms of activity synchronization in group living ungulates are not well understood. In a case study on herd of 15 Gasconne beef cows with calves observed during a total of 25 summer daylight periods in 2004 and 2005, we examined whether cows similar to each other in body weight or in reproductive status were more synchronized and whether the timing of activity switches were determined by specific leading animals. We calculated the synchronization of all possible pairs of cows in the herd and tested the effects of similarity in body weight and in reproductive status (lactating versus non-lactating) on synchronization in the pair. Further, we assessed whether any specific individuals, and especially the dominant cows, were more able, through their own activity switch, to incite another cow to follow shortly with her switch in activity. We found that body weight differences had a negative influence on pair synchronization (GLMM, F1,65 = 6.79; p < 0.05), but reproductive status did not affect the synchronization. Cows' individual identity explained only a small proportion (<2%) of variability in intervals between switches of subsequent cows. Furthermore, dominance status of an individual cow did not correlate with mean interval between her activity switches and activity switches of the next cow (lying down: Spearman correlation, rs = -0.16, n = 14, p > 0.10; standing up: Spearman correlation, rs = -0.38, n = 14, p > 0.10), indicating that there were no leading animals initiating switches in activity in our herd.
Keywords: Beef cattle; Activity synchronization; Leadership; Dominance
|
|
Sara J. Shettleworth. (1999). Female mate choice in swordtails and mollies: symmetry assessment or Weber's law? Anim. Behav., 58(5), 1139–1142.
|
|
Sappington, B. K. F., McCall, C. A., Coleman, D. A., Kuhlers, D. L., & Lishak, R. S. (1997). A preliminary study of the relationship between discrimination reversal learning and performance tasks in yearling and 2-year-old horses. Appl. Anim. Behav. Sci., 53(3), 157–166.
Abstract: A study was conducted to determine the relationship between discrimination reversal learning and performance tasks in horses. Ten yearling and seven 2-year-old mares and geldings of Arabian (n = 4), Quarter Horse (n = 9), and Thoroughbred (n = 4) breeding were given a two-choice discrimination task in which either a black or a white bucket contained a food reward for ten trials per day during 19 test days. The spatial position of the buckets was varied on a random schedule. The rewarded bucket color was reversed each time a subject met criterion of eight correct choices per day for 2 consecutive days. Discrimination reversal testing was followed by 6 days of performance tasks: three crossing a wooden bridge and three jumping an obstacle to reach food and conspecifics, within a maximum allotted time of 15 min day-1. Total reversals attained by the horses were low (x = 1.5 +/- 0.9). All subjects did attain at least one reversal, and six had two or more reversals. No differences (P > .05) were detected between ages or sexes, nor among breeds in discrimination reversal learning or performance test measurements. However, there was a trend towards a breed difference (P <= 0.09) in the mean number of correct responses to the first reversal criterion. Correlations between reversal learning results and performance task results were extremely low, indicating that the discrimination reversal learning test was not useful for predicting success at these performance tasks. Results from the two performance tasks also showed little correlation (r = 0.04, P < 0.91), indicating that horses might not use the same approach when solving the problem of crossing these two obstacles. The overall poor performance of the horses on the discrimination reversal task suggests horses may have difficulty reversing previously learned tasks.
|
|
Sankey, C., Richard-Yris, M. - A., Leroy, H., Henry, S., & Hausberger, M. (2010). Positive interactions lead to lasting positive memories in horses, Equus caballus. Anim. Behav., 79(4), 869–875.
Abstract: Social relationships are important in social species. These relationships, based on repeated interactions, define each partner's expectations during the following encounters. The creation of a relationship implies high social cognitive abilities which require that each partner is able to associate the positive or negative content of an interaction with a specific partner and to recall this association. In this study, we tested the effects of repeated interactions on the memory kept by 23 young horses about humans, after 6 and 8 months of separation. The association of a reward with a learning task in an interactional context induced positive reactions towards humans during training. It also increased contact and interest, not only just after training, but also several months later, despite no further interaction with humans. In addition, this ‘positive memory’ of humans extended to novel persons. Overall, positive reinforcement enhanced learning and memorization of the task itself. These findings suggest remarkable social cognitive abilities that can be transposed from intraspecific to interspecific social contexts.
|
|
Sanga, U., Provenza, F. D., & Villalba, J. J. (2011). Transmission of self-medicative behaviour from mother to offspring in sheep. Anim. Behav., 82(2), 219–227.
Abstract: Herbivores challenged by diets with high concentrations of tannins learn by individual experience to self-select medicinal compounds such as polyethylene glycol (PEG), which neutralizes the negative postingestive effects of tannins. We investigated the transmission of this acquired self-medicative behaviour from mother to offspring. One group of ewes (experienced, N = 8) was conditioned to associate the beneficial effects of PEG after consuming a tannin-rich diet. Ewes ingested a meal of high-tannin food and were then offered PEG. Subsequently, ewes ingested the same tannin-rich meal and were then offered a food (grape pomace; control) that did not have the medicinal effects of PEG. After conditioning, the experienced group and a naïve group of ewes (N = 8) were given a choice between the high-tannin food, PEG and grape pomace. Experienced ewes showed higher intake and preference for PEG than did naïve ewes (P < 0.05). Subsequently, experienced and naïve ewes with their naïve lambs, as well as a group of naïve lambs without their mothers (N = 8), were exposed to the tannin-rich diet, PEG and grape pomace. Lambs were then tested for their ability to self-medicate with PEG by offering them a choice between the tannin-rich diet, PEG and grape pomace. Lambs from experienced and naïve mothers showed a higher preference for PEG than did lambs exposed without their mothers (P = 0.05). Thus, the presence of the mother (experienced or naïve) was important for naïve lambs to learn about the medicinal benefits of PEG. We conclude that the mother's presence per se may increase the efficiency of creating new knowledge, such as preference for a medicine, within a group, beyond transmitting and maintaining this knowledge across generations.
Keywords: feeding; food selection; Ovis aries; polyethylene glycol; sheep; tannins
|
|
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.
|
|
Salzen, E. A., & Cornell, J. M. (1968). Self-perception and species recognition in birds. Behaviour, 30(1), 44–65.
|
|
Sakai, M., Hishii, T., Takeda, S., & Kohshima, S. (2006). Laterality of flipper rubbing behaviour in wild bottlenose dolphins (Tursiops aduncus): Caused by asymmetry of eye use? Behav. Brain. Res., 170(2), 204–210.
Abstract: To determine whether wild Indo-Pacific bottlenose dolphins (Tursiops aduncus) at Mikura Island, Japan, show asymmetry of eye or flipper use during a social behaviour, we investigated the laterality of flipper-to-body (F-B) rubbing, in which one dolphin (“rubber”) rubs the body of another (“rubbee”) with its flipper. We analysed 382 episodes of video-recorded F-B rubbings performed by identified individuals (N = 111 rubbers). F-B rubbing was conducted significantly more frequently with the left flipper than with the right flipper. The duration of F-B rubbings was also significantly longer with the left flipper than with the right flipper. Of 20 dolphins, nine individuals showed significant left-side bias as the rubber in this behaviour, whereas no dolphins showed significant right-side bias. The results indicate a population-level left-side bias of the rubber in F-B rubbing. An analysis of the swimming configurations during this behaviour suggests that the asymmetry in F-B rubbing was caused not only by the laterality of the rubber, but by a preference for use of the left eye in both dolphins during this behaviour. Dolphins used the left eye significantly more frequently than the right eye during the inquisitive behaviour, while they showed no significant bias in flipper use during the object-carrying behaviour. These facts also suggest that the asymmetry of F-B rubbing is caused by the preference for using the left eye. Significant left-side bias was observed only in F-B rubbings initiated by the rubbee, in which the rubbee determined its position during this behaviour. This suggests that this behavioural asymmetry was enhanced by the rubbees choosing the left side of the rubber to ensure better and longer rubs.
|
|
Rørvang, M. V., Ahrendt, L. P., & Christensen, J. W. (2015). A trained demonstrator has a calming effect on naïve horses when crossing a novel surface. Appl. Anim. Behav. Sci., 171, 117–120.
Abstract: Abstract Habituated horses have been found to have a calming effect on conspecifics in fear-eliciting situations. In practice, experienced horses are often used as companions when young horses are introduced to potentially frightening situations, like loading onto a trailer. However, studies of social transmission of habituation in horses are scarce. This study investigated if demonstration by a habituated demonstrator horse influenced the willingness of young Icelandic horses (n = 22, 3 years old) to cross a novel surface. Observer horses (n = 11) were allowed to observe the similarly aged demonstrator horse being led five times across a novel surface. Immediately afterwards the observer horses were given the opportunity to cross the novel surface themselves to obtain food on the other side. Controls (n = 11) were allowed to observe the demonstrator eating on the opposite side of the novel surface but not the demonstration of crossing the novel surface. All observers and controls succeeded the task, but observers had significantly lower average and maximum heart rate, compared to controls. This result suggests a calming effect of the demonstration, which could be exploited for habituation training of horses in fear-eliciting situations.
Keywords: Fear; Habituation; Social learning; Social transmission; Heart rate
|