|
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.
|
|
|
Feist, J. D., & McCullough, D. R. (1976). Behavior patterns and communication in feral horses. Z. Tierpsychol., 41(4), 337–371.
Abstract: The social behavior of feral horses was studied in the western United States. Stable harem groups with a dominant stallion and bachelor hermaphrodite hermaphrodite groups occupied overlapping home ranges. Groups spacing, but not territoriality, was expressed. Harem group, stability resulted from strong dominance by dominant stallions, and fidelity of group members. Eliminations of group members were usually marked by urine of the dominant stallion. Hermaphrodite-hermaphrodite aggression involved spacing between harems and dominance in bachelor groups. Marking with feces was important in hermaphrodite-hermaphrodite interactions. Foaling occurred in May and early June, following the post-partum estrous. All breeding was done by harem stallions. Young were commonly nursed through yearling age. These horses showed social organizations similar to other feral horses and plains zebras.
|
|
|
Gajdon, G. K., Fijn, N., & Huber, L. (2006). Limited spread of innovation in a wild parrot, the kea (Nestor notabilis). Anim. Cogn., 9(3), 173–181.
Abstract: In the local population of kea in Mount Cook Village, New Zealand, some keas open the lids of rubbish bins with their bill to obtain food scraps within. We investigated the extent to which this innovation has spread in the local population, and what factors limit the acquisition of bin opening. Only five males of 36 individually recognised birds were observed to have performed successful bin opening. With one exception there were always other keas present, watching successful bin opening. Seventeen additional individuals were seen to have benefitted from lid opening. Their foraging success was less than that of the bin openers. Social status of bin openers did not differ from scrounging males. Among the individuals that were regularly seen at the site of the bins but were not successful in bin opening, social status and the ratio of feeding directly from open bins correlated with the amount of opening attempts. We conclude that scrounging facilitated certain behavioural aspects of bin opening rather than inhibiting them. The fact that only 9% of opening attempts were successful, and the long period of time required to increase efficiency in lid opening shows that mainly individual experience, and to a lesser extent insight and social learning, play key roles in acquisition of the opening technique. The results indicate that the spread of innovative solutions of challenging mechanical problems in animals may be restricted to only a few individuals.
|
|
|
Giles, N., & Tupper, J. (2006). Equine interspecies aggression (Vol. 159).
|
|
|
Grosenick, L., Clement, T. S., & Fernald, R. D. (2007). Fish can infer social rank by observation alone. Nature, 445(7126), 429–432.
Abstract: Transitive inference (TI) involves using known relationships to deduce unknown ones (for example, using A > B and B > C to infer A > C), and is thus essential to logical reasoning. First described as a developmental milestone in children, TI has since been reported in nonhuman primates, rats and birds. Still, how animals acquire and represent transitive relationships and why such abilities might have evolved remain open problems. Here we show that male fish (Astatotilapia burtoni) can successfully make inferences on a hierarchy implied by pairwise fights between rival males. These fish learned the implied hierarchy vicariously (as 'bystanders'), by watching fights between rivals arranged around them in separate tank units. Our findings show that fish use TI when trained on socially relevant stimuli, and that they can make such inferences by using indirect information alone. Further, these bystanders seem to have both spatial and featural representations related to rival abilities, which they can use to make correct inferences depending on what kind of information is available to them. Beyond extending TI to fish and experimentally demonstrating indirect TI learning in animals, these results indicate that a universal mechanism underlying TI is unlikely. Rather, animals probably use multiple domain-specific representations adapted to different social and ecological pressures that they encounter during the course of their natural lives.
|
|
|
Heitor, F., do Mar Oom, M., & Vicente, L. (2006). Social relationships in a herd of Sorraia horses Part I. Correlates of social dominance and contexts of aggression. Behav. Process., 73(2), 170–177.
Abstract: Factors related to dominance rank and the functions of aggression were studied in a herd of Sorraia horses, Equus caballus, under extensive management. Subjects were 10 adult mares 5-18 years old and a stallion introduced into the group for breeding. Dominance relationships among mares were clear, irrespective of rank difference, and remained stable after introduction of the stallion. The dominance hierarchy was significantly linear and rank was positively correlated with age and total aggressiveness. Higher-ranking mares received lower frequency and intensity of agonistic interactions. Nevertheless, higher-ranking dominants were not more likely to elicit submission from their subordinates than lower-ranking dominants. Neither close-ranking mares nor mares with less clear dominance relationships were more aggressive towards each other. Agonistic interactions seemed to be used more importantly in regulation of space than to obtain access to food or to reassert dominance relationships. Contexts of aggression were related to mare rank. The results suggest that dominance relationships based on age as a conventional criterion were established to reduce aggressiveness in a herd where the costs of aggression are likely to outweigh the benefits.
|
|
|
Hemelrijk, C. K., & Wantia, J. (2005). Individual variation by self-organisation. Neurosci Biobehav Rev, 29(1), 125–136.
Abstract: In this paper, we show that differences in dominance and spatial centrality of individuals in a group may arise through self-organisation. Our instrument is a model, called DomWorld, that represents two traits that are often found in animals, namely grouping and competing. In this model individual differences grow under the following conditions: (1) when the intensity of aggression increases and grouping becomes denser, (2) when the degree of sexual dimorphism in fighting power increases. In this case the differences among females compared to males grow too, (3) when, upon encountering another individual, the tendency to attack is 'obligate' and not conditional, namely 'sensitive to risks'. Results resemble phenomena described for societies of primates, mice, birds and pigs.
|
|
|
Hodgson, D., Howe, S., Jeffcott, L., Reid, S., Mellor, D., & Higgins, A. (2005). Effect of prolonged use of altrenogest on behaviour in mares (Vol. 169).
Abstract: Erratum in:
Vet J. 2005 May;169(3):321.
Corrected and republished in:
Vet J. 2005 May;169(3):322-5.
Oral administration of altrenogest for oestrus suppression in competition horses is believed to be widespread in some equestrian disciplines, and can be administered continuously for several months during a competition season. To examine whether altrenogest has any anabolic or other potential performance enhancing properties that may give a horse an unfair advantage, we examined the effect of oral altrenogest (0.044 mg/kg), given daily for a period of eight weeks, on social hierarchy, activity budget, body-mass and body condition score of 12 sedentary mares. We concluded that prolonged oral administration of altrenogest at recommended dose rates to sedentary mares resulted in no effect on dominance hierarchies, body mass or condition score.
|
|
|
Houpt, K. A. (1976). Animal behavior as a subject for veterinary students. Cornell Vet, 66(1), 73–81.
Abstract: Knowledge of animal behavior is an important asset for the veterinarian; therefore a course in veterinary animal behavior is offered at the New York State College of Veterinary Medicine as an elective. The course emphasizes the behavior of those species of most interest to the practicing veterinarian: cats, dogs, horses, cows, pigs and sheep. Dominance heirarchies, animal communication, aggressive behavior, sexual behavior and maternal behavior are discussed. Play, learning, diurnal cycles of activity and sleep, and controls of ingestive behavior are also considered. Exotic and zoo animal behaviors are also presented by experts in these fields. The critical periods of canine development are related to the optimum management of puppies. The behavior of feral dogs and horses is described. The role of the veterinarian in preventing cruelty to animals and recognition of pain in animals is emphasized. Whenever possible behavior is observed in the laboratory or on film.
|
|
|
Houpt, K. A., & Wolski, T. R. (1980). Stability of equine hierarchies and the prevention of dominance related aggression. Equine Vet J, 12(1), 15–18.
Abstract: The dominance hierarchy of a herd of 10 Thoroughbred mares was determined twice, at an interval of 18 months, using paired feeding tests. Each mare's rank was correlated significantly between the 2 tests. This indicated that the hierarchy within the herd was stable. The offspring of dominant and subordinate mares were also tested for dominance in their own age groups. The offspring of dominant mares tended to be near the top of the hierarchy while those of middle and low ranking mares were not consistently found in the middle or bottom of their own hierarchies. Paired feeding tests were carried out on 8 ponies. During tests the time that each pony spent eating and the ponies' aggressive interactions were recorded. Two situations were used. Each pony-pair was tested when both ponies were in the same paddock and also when they were separated by a rail fence. The subordinate ponies spent significantly more time eating and the domonant pony was significantly less aggressive, when the pony-pair was separated by a fence than when they were in one paddock. It was concluded that the dominance hierarchies of adult horse groups changed very little over time and that the foals of dominant mares will tend to be dominant in their own age groups. Management practices can be used to reduce aggression and consequent injury that may arise in group feeding situations.
|
|