|
|
Saayman, G. S. (1971). Behaviour of the adult males in a troop of free-ranging Chacma baboons (Papio ursinus). Folia Primatol (Basel), 15(1), 36–57.
|
|
|
|
Neumann, C., Duboscq, J., Dubuc, C., Ginting, A., Irwan, A. M., Agil, M., et al. (2011). Assessing dominance hierarchies: validation and advantages of progressive evaluation with Elo-rating. Animal Behaviour, 82(4), 911–921.
|
|
|
|
Feist, J. D., & McCullough, D. R. (1975). Reproduction in feral horses. J Reprod Fertil Suppl, (23), 13–18.
Abstract: A behavioural study of feral horses was conducted on the Pryor Mountain Wild Horse Range in the western United States. All 270 horses on the Range were identified individually. The sex ratio was nearly balanced. Foal to adult female ratio was 43-2:100. Morality was concentrated among foals and old horses. Horses were organized as forty-four harem groups each with a dominant stallion, one to two immature stallions, one to three immature mares, one to three adult mares and their yearling and foal offspring, and 23 bachelor groups of one to eight stallions. Harem groups were quite stable year-round because of dominance and leadership by the stallions and group fidelity by mares and their offsring. Most changes occurred during the breeding season and involved immature females. Defeat of dominant stallions was infrequent. Immature males were tolerated because of their submissive behaviour. Bachelor stallion groups were inherently unstable. Mares came into heat after foaling in May/June, and were mated by harem stallions only.
|
|
|
|
Anderson, J. R., Fornasieri, I., Ludes, E., & Roeder, J. - J. (1992). Social processes and innovative behaviour in changing groups of lemur fulvus. Behav. Process., 27(2), 101–112.
Abstract: A group of brown lemurs was presented with one or two baited food-boxes requiring a specific type of motor response in order to be opened. Subsequently, four groups containing different combinations of experienced individuals from the original group and naive individuals were tested. Solutions to the problem and access to the food were recorded and considered in relation to social factors. In the original group, two adult males learned to open the boxes, with one male increasingly preventing the other from approaching. In the second group, with the subordinate male and certain females removed, the dominant male tolerated successful performances by a juvenile female. Group 3 consisted of three passive female participants from the original group and a naive female; one of the three original females now became the sole box-opener. The introduction of the subordinate male from the original group into the all-female group led to a sharing of box-opening by this subject and the skilled female. In the final group, intense aggression toward the skilled female by a new, naive adult male resulted in two previously passive females succeeding on some occasions. In lemurs, at least some `scroungers' appear able to learn to perform a new act when the social context permits.
|
|
|
|
Fujita, K., Kuroshima, H., & Masuda, T. (2002). Do tufted capuchin monkeys (Cebus apella) spontaneously deceive opponents? A preliminary analysis of an experimental food-competition contest between monkeys. Anim. Cogn., 5(1), 19–25.
Abstract: A new laboratory procedure which allows the study of deceptive behavior in nonhuman primates is described. Pairs of tufted capuchin monkeys faced each other in a food-competition contest. Two feeder boxes were placed between the monkeys. A piece of food was placed in one of the boxes. The subordinate individual was able to see the food and to open the box to obtain the bait. A dominant male was unable to see the food or to open the box but was able to take the food once the box was opened by the subordinate. In experiment 1, two of four subordinate monkeys spontaneously started to open the unbaited box first with increasing frequency. Experiment 2 confirmed that this “deceptive” act was not due to a drop in the rate of reinforcement caused by the usurping dominant male, under the situation in which food sometimes automatically dropped from the opened box. In experiment 3, two subordinate monkeys were rerun in the same situation as experiment 1. One of them showed some recovery of the “deceptive” act but the other did not; instead the latter tended to position himself on the side where there was no food before he started to open the box. Although the results do not clearly indicate spontaneous deception, we suggest that operationally defined spontaneous deceptive behaviors in monkeys can be analyzed with experimental procedures such as those used here.
|
|
|
|
Bang, A., Deshpande, S., Sumana, A., & Gadagkar, R. (2010). Choosing an appropriate index to construct dominance hierarchies in animal societies: a comparison of three indices. Animal Behaviour, 79(3), 631–636.
Abstract: A plethora of indices have been proposed and used to construct dominance hierarchies in a variety of vertebrate and invertebrate societies, although the rationale for choosing a particular index for a particular species is seldom explained. In this study, we analysed and compared three such indices, viz Clutton-Brock et al.'s index (CBI), originally developed for red deer, Cervus elaphus, David's score (DS) originally proposed by the statistician H. A. David and the frequency-based index of dominance (FDI) developed and routinely used by our group for the primitively eusocial wasps Ropalidia marginata and Ropalidia cyathiformis. Dominance ranks attributed by all three indices were strongly and positively correlated for both natural data sets from the wasp colonies and for artificial data sets generated for the purpose. However, the indices differed in their ability to yield unique (untied) ranks in the natural data sets. This appears to be caused by the presence of noninteracting individuals and reversals in the direction of dominance in some of the pairs in the natural data sets. This was confirmed by creating additional artificial data sets with noninteracting individuals and with reversals. Based on the criterion of yielding the largest proportion of unique ranks, we found that FDI is best suited for societies such as the wasps belonging to Ropalidia, DS is best suited for societies with reversals and CBI remains a suitable index for societies such as red deer in which multiple interactions are uncommon.
|
|
|
|
Mazurek, M., McGee, M., Minchin, W., Crowe, M. A., & Earley, B. (2011). Is the avoidance distance test for the assessment of animals' responsiveness to humans influenced by either the dominant or flightiest animal in the group? Appl. Anim. Behav. Sci., 132(3-4), 107–113.
Abstract: A previously described (Windschnurer et al., 2009) avoidance distance test was used to assess animals’ fear of humans in order to quantify the human–animal relationship (HAR). This study investigated the influence of the dominant and flightiest animals within a group on the responsiveness of animals during the avoidance distance test. Eighty-eight pregnant heifers comprised of four different genotypes were used (22 animals per genotype): Limousin × Holstein-Friesian, Limousin × Simmental, Charolais × Limousin, and Charolais × Simmental. Sixty of the 88 heifers were group housed (n = 5) into 12 pens with 3 pens per breed, while 28 heifers were singly housed (seven heifers per breed). A reactivity test was performed on days 10, 18, 25 and 30 post-housing on the singly housed heifers, and then on the group housed heifers, on the same days, to calculate a reactivity score. On days 33 and 37 flight and dominance tests, respectively, were performed to identify the flightiest and the dominant animal within each group. On day 41, an avoidance test, measuring both the avoidance distance towards a familiar and an unfamiliar human, was performed on all heifers. No difference (P > 0.05) in reactivity scores was found between the genotypes, between pens for the group housed heifers or between singly housed and group housed heifers (P = 0.28). The avoidance distance (AD) of singly (S) housed heifers towards a familiar (F) (ADSF) human was shorter (P < 0.001) than the avoidance distance of group (G) housed heifers towards an unfamiliar human (ADSU). The ADSF and ADGF were correlated with the ADSU and ADGU (R = 0.87 for singly housed heifers; R = 0.61 for group housed heifers, P < 0.001). For the singly housed heifers, no correlation was observed between reactivity score and ADSF (R = 0.36, P = 0.18), whereas the reactivity score and ADSU were correlated (R = 0.68, P = 0.004). For the group housed heifers no significant correlation was detected between the reactivity score and ADGF (R = 0.18, P = 0.22) or ADGU (R = −0.11, P = 0.39). No influence of the most dominant animal and the flightiest animals was found on the behaviour of the group in term of avoidance distance and reactivity (P > 0.05). It is concluded that the assessment of the fear of the animals towards humans using the avoidance test at the feed bunk may be useful for singly and group housed heifers and that the leaders of a group such as the flightiest animal or the dominant animal did not influence the avoidance distance test.
|
|
|
|
Chiesa, A. D., Pecchia, T., Tommasi, L., & Vallortigara, G. (2006). Multiple landmarks, the encoding of environmental geometry and the spatial logics of a dual brain. Anim. Cogn., 9(4), 281–293.
Abstract: A series of place learning experiments was carried out in young chicks (Gallus gallus) in order to investigate how the geometry of a landmark array and that of a walled enclosure compete when disoriented animals could rely on both of them to re-orient towards the centre of the enclosure. A square-shaped array (four wooden sticks) was placed in the middle of a square-shaped enclosure, the two structures being concentric. Chicks were trained to ground-scratch to search for food hidden in the centre of the enclosure (and the array). To check for effects of array degradation, one, two, three or all landmarks were removed during test trials. Chicks concentrated their searching activity in the central area of the enclosure, but their accuracy was inversely contingent on the number of landmarks removed; moreover, the landmarks still present within the enclosure appeared to influence the shape of the searching patterns. The reduction in the number of landmarks affected the searching strategy of chicks, suggesting that they had focussed mainly on local cues when landmarks were present within the enclosure. When all the landmarks were removed, chicks searched over a larger area, suggesting an absolute encoding of distances from the local cues and less reliance on the relationships provided by the geometry of the enclosure. Under conditions of monocular vision, chicks tended to rely on different strategies to localize the centre on the basis of the eye (and thus the hemisphere) in use, the left hemisphere attending to details of the environment and the right hemisphere attending to the global shape.
|
|
|
|
Hewitt, S. E., Macdonald, D. W., & Dugdale, H. L. (2009). Context-dependent linear dominance hierarchies in social groups of European badgers, Meles meles. Anim. Behav., 77(1), 161–169.
Abstract: A social hierarchy is generally assumed to exist in those mammalian societies in which the costs and benefits of group living are distributed unevenly among group members. We analysed infrared closed-circuit television footage, collected over 3 years in Wytham Woods, Oxfordshire, to test whether social groups of European badgers have dominance hierarchies. Analysis of directed aggression between dyads revealed linear dominance hierarchies in three social-group-years, but patterns within social groups were not consistent across years. Dominance hierarchies were significantly steeper than random in five out of six social-group-years. In those social-group-years where a linear hierarchy was determined, there was an effect of sex on dominance rank, with females gaining significantly higher rank than males in two social-group-years. Overall, rank was not related to age, nor did it appear to affect the likelihood of an individual being wounded, or an individual's breeding status. The latter resulted from nonorthogonality between sex and breeding status, as there were only two breeding males. Overall, hierarchies were primarily dominated by breeding females, and may occur when breeding competition arises. Relatedness, unreciprocated allogrooming and sequential allomarking were not consistently related to levels of directed aggression across social-group-years. We suggest that dominance structures within European badger groups may be context dependent, with future study required to complete our understanding of where, and when, they arise.
|
|
|
|
Puppe, B., Langbein, J., Bauer, J., & Hoy, S. (2008). A comparative view on social hierarchy formation at different stages of pig production using sociometric measures. Livestock Science, 113(2-3), 155–162.
Abstract: A standardised and comprehensive approach to describe dominance relationships in gregarious farm animals quantitatively was recently developed, incorporating a combination of appropriate sociometric measures. The present study applied this approach to a comparative analysis of the social hierarchies within 57 groups of domestic pigs at different age/production stages with a total of 496 animals. Unacquainted pigs were grouped to three age categories which correspond to the typical production stages: weaned pigs (PIG28, 12 groups), growing pigs (PIG80, 16 groups), and reproductive sows (SOW, 29 groups). Based on observed agonistic interactions, sociometric values were calculated both at the dyadic and at the group level and may be considered as preliminary reference values for further studies. As indicated by the respective values of the Kendall index (PIG28: 0.66, tested as significant in 69.0% of the observed groups; PIG80: 0.71, 87.5%; SOW: 0.61, 69.0%), and the improved Landau index (PIG28: 0.70, 75.0%; PIG80: 0.72, 93.7%; SOW: 0.71, 72.4%), a social organisation towards a quasi-linear social hierarchy was predominantly developed throughout all age/production categories. However, compared to weaned and growing pigs, sows were characterised by significant differences concerning establishment (fewer agonistic interactions) and kind (more unknown dyads, fewer two-way and significant dyads, higher directional consistency index) of their social hierarchy. It seems that sows have effectively adapted their agonistic behaviour towards pen-mates to regulate social dominance relationships, whereas younger pigs frequently display agonistic interactions also to gain additional experience on social cues (e.g. the fighting ability of an opponent). Hence, it is concluded that the effective experience of socialisation during sensitive periods may increase the social skills of pigs which in turn can improve their welfare and health, e.g. by adjusted aggressive behaviour. The consideration of comparable and standardised sociometric measures in livestock breeding may help to improve husbandry conditions.
|
|
