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Author |
i Rios, J.F.; Houpt, K. |
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Sexual behavior in geldings |
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Journal Article |
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Year |
1995 |
Publication |
Applied Animal Behaviour Science |
Abbreviated Journal |
Appl. Anim. Behav. Sci. |
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46 |
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1-2 |
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133-135 |
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Abstract
In response to a request published in Equus, a magazine for those interested in horses, 85 owners of older geldings exhibiting sexual behavior completed history forms. The mean age of geldings was 16 f 5 years. Only 39 of the owners had had the gelding for at least a year before the behavior was noted. These cases could be used to determine the true age of onset of the problem. When log survivorship was used to determine whether there were one or two different populations, a break or change in the slope at age 16 indicated that there are two populations. One population shows the behavior from the time of castration and the other first exhibits the behavior in old age, possibly in response to an ACTH secreting pituitary adenoma. A total of 40% of the horses were Quarterhorses, the most numerous breed in the US; 78% of the horses were purebreds. Fewer than half the owners knew the age at which their horse had been castrated because they did not own the horse at the time.
The mean age at castration, when known, was 3.3 f 2.5 years. The reason for contacting us was sexual behavior (70%), aggression (24%). or some other problem ( 1 o/o). Whether or not aggression was the presenting problem, most of the horses showed aggression (95%), particularly towards other geldings (88%)) but also towards people (3 1%). Copulatory behavior (mounting) was shown by 69% of the geldings and half of those were able to intromit. These findings indicate that the sexual behavior of geldings is a problem for owners and that aggression usually accompanies sexual behavior.
The owners were encouraged to send serum samples taken before and after human chorionic gonadotropin (HCG) administration for testosterone and estrone sulfate analysis to determine whether residual testicular tissue was responsible for the horse’s behavior. Of the 14 horses tested, only one had elevated levels of testosterone indicating that there was residual testicular tissue. A total of six of the owners agreed to treat their horses with cyproheptadine at a dose of 8 mg day- ’ gradually increased to 88 mg day- ’ per horse. A total of three of the horses showed a decline in sexual and aggressive behavior, one got worse and two had side effects and treatment was withdrawn. |
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Equine Behaviour @ team @ |
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3627 |
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Bouskila, A.,; Lourie,E.; de Vries, H.; Hermans, Z.M .; van Dierendonck, M. |
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Title |
Sex, but not relatedness nor age, affect the social network of horses in a semi-natural reserve |
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Conference Article |
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Year |
2015 |
Publication |
Proceedings of the 3. International Equine Science Meeting |
Abbreviated Journal |
Proc. 3. Int. Equine. Sci. Mtg |
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For some time now, social network analysis provides tools to describe concisely the social structure of animals. Nevertheless, the factors that shape the social network and determine the frequency of different types of affiliations are often unclear. For example, the effects of relatedness on social networks have been only studied on relatively few species. Both among social or sub-social species the effects ranged from no effect to a substantial effect. Here we test the hypothesis that relatedness has an effect on the social network of horses (Equus caballus) that live freely in semi-natural conditions, and specifically, that individuals with high values of relatedness to their neighbors in the network will have fewer links Wolf et al, 2011). This hypothesis is based on the notion that related individuals have common interests and are likely to assist each other, and may need less links to other, unrelated individuals. In addition, individuals of similar age and sex are likely to have common needs, and thus are more likely to be associated. We thus tested a second hypothesis: homophily to individuals with similar age and sex will have a role in determining the associations within the social network. The field study was conducted on 27 horses in the Blauwe Kamer reserve in the Netherlands (1.1 sq km). We videotaped horses and their groups and used the information from 22 horses, after excluding the five foals from the analysis. Relatedness was calculated from the pedigree, which was based on parentage, determined by DNA analysis. The social network was constructed based on spatial proximity data. We assessed the influence of relatedness, age-homophily and sex-homophily on the network structure with Multiple Regression Quadratic Assignment Procedure (MRQAP) (Krackhardt 1988), with the R package sna. The results show that there was no significant effect of relatedness on the network, nor an effect of age-homophily. Nevertheless, we found a significant effect of sex-homophily, the tendency of individuals to associate with individuals of the same sex. We argue that the lack of a relatedness effect is not likely to have been caused due to the inability to detect who is kin. The structured social system in horses includes strong associations between often unrelated individuals, alongside with young individuals leaving their natal harem as part of the inherent inbreeding avoidance (Linklater & Cameron 2009; Boyd et al. in press). The significant effect of sex-homophily could stem from the protection females get from associations with other females, e.g., in the reduction of harassment from males. Previous studies on feral horses showed that mares that were better connected with other females in their harem benefited from higher survival rates to their foals (Cameron et al. 2009). The associations among bachelor males could also contribute to the strength of the sex-homophily effect.
In order to generalize from our results, one needs to examine additional populations of horses, because the conditions in the Blauwe Kamer reserve may not be representative, mainly due to the limited opportunity for dispersal in a restricted area.
Keywords: Long-term affiliation; spatial proximity, kin detection
Boyd, L., Scorolli, A. L., Nowzari, H., & Bouskila, A. (2016). Chapter 2: Social organization. In J. I. Ransom, & P. Kaczensky (Eds.), Wild equids. Baltimore, Maryland (in press): The Johns Hopkins University Press.
Cameron, E. Z., Setsaas, T. H., & Linklater, W. L. (2009). Social bonds between unrelated females increase reproductive success in feral horses. Proceedings of the National Academy of Sciences, 106(33), 13850-13853
Krackhardt, D. (1988). Predicting with networks: Nonparametric multiple regression analysis of dyadic data. Social Networks, 10(4), 359-381.
Linklater, W. L., & Cameron, E. Z. (2009). Social dispersal but with philopatry reveals incest avoidance in a polygynous ungulate. Animal Behaviour, 77(5), 1085-1093.
Wolf, J. B., Traulsen, A., & James, R. (2011). Exploring the link between genetic relatedness r and social contact structure k in animal social networks. The American Naturalist, 177(1), 135-142. |
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Bouskila, A. |
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Equine Behaviour @ team @ |
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5881 |
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Author |
Murphy, J.; Waldmann, T.; Arkins, S. |
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Title |
Sex differences in equine learning skills and visuo-spatial ability |
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Journal Article |
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Year |
2004 |
Publication |
Applied Animal Behaviour Science |
Abbreviated Journal |
Appl. Anim. Behav. Sci. |
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87 |
Issue |
1-2 |
Pages |
119-130 |
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Horses; Sex differences; Visuo-spatial ability; Learning |
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There is evidence of superior visuo-spatial ability in males compared to females in most species investigated to-date. However, no known studies have addressed this issue in the equine. Equine visuo-spatial ability was investigated using a novel test apparatus with a sample of 62 horses (males=34 and females=28) during a series of six tests, where the horses were required to access a food source. The test apparatus consisted of a series of four adjacent stalls, each of which had a feed bin and a moveable barrier. The test apparatus was designed such that the breastplate barriers controlled and limited access by the horses to feed bins in all but one stall during each test. Male horses performed such that there were significant differences (P<0.05) in the ability of the subjects to complete all six tests in a mean time of 30 s or less per test. There were significant differences in mean completion times for male subjects between test 1 and test 2 (P<0.05), test 1 and test 3 (P<0.001), test 1 and test 4 (P<0.05) and test 1 and test 5 (P<0.05). There were no significant differences in mean completion times between any of the six tests for female subjects. Males had a lower mean total number of errors during all tests. Male horses also successfully completed significantly more tests than females (P<0.05). These results provide the first behavioural demonstration of superior visuo-spatial ability in male horses, similar to that reported in other species. |
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Equine Behaviour @ team @ |
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3560 |
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Schanz, L.; Krueger, K.; Hintze, S. |
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Title |
Sex and Age Don't Matter, but Breed Type Does--Factors Influencing Eye Wrinkle Expression in Horses |
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Journal Article |
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Year |
2019 |
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Frontiers in Veterinary Science |
Abbreviated Journal |
Front. Vet. Sci. |
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6 |
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154 |
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Identifying valid indicators to assess animals' emotional states is a critical objective of animal welfare science. In horses, eye wrinkles above the eyeball have been shown to be affected by pain and other emotional states. From other species we know that individual characteristics, e.g. age in humans, affect facial wrinkles, but it has not yet been investigated whether eye wrinkle expression in horses is systematically affected by such characteristics. Therefore, the aim of this study was to assess how age, sex, breed type, body condition and coat colour affect the expression and/or the assessment of eye wrinkles in horses. To this end, we adapted the eye wrinkle assessment scale from Hintze et al. (2016) and assessed eye wrinkle expression in pictures taken from the left and the right eye of 181 horses in a presumably neutral situation, using five outcome measures: a qualitative first impression reflecting how worried the horse is perceived by humans, the extent to which the brow is raised, the number of wrinkles, their markedness and the angle between a line through both corners of the eye and the topmost wrinkle. All measures could be assessed highly reliable with respect to intra- and inter-observer agreement. Breed type affected the width of the angle (F2, 114 = 8.20, p < 0.001), with thoroughbreds having the narrowest angle (M = 23.80, SD = 1.60), followed by warmbloods (M = 28.00, SD = 0.60), and coldbloods (M = 31.00, SD = 0.90). None of the other characteristics affected any of the outcome measures, and eye wrinkle expression did not differ between the left and the right eye area (all p-values > 0.05). In conclusion, horses' eye wrinkle expression and its assessment in neutral situations was not systematically affected by the investigated characteristics, except for 'breed type', which accounted for some variation in 'angle'; how much eye wrinkle expression is affected by emotion or perhaps mood needs further investigation and validation. |
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2297-1769 |
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Equine Behaviour @ team @ |
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6578 |
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Author |
Lansade, L.; Pichard, G.; Leconte, M. |
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Title |
Sensory sensitivities: Components of a horse's temperament dimension |
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Journal Article |
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Year |
2008 |
Publication |
Applied Animal Behaviour Science |
Abbreviated Journal |
Appl. Anim. Behav. Sci. |
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114 |
Issue |
3-4 |
Pages |
534-553 |
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Keywords |
Horse; Equus caballus; Temperament; Sensory sensitivity; Behavioural tests |
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Temperament is an important factor when working with horses. Behavioural tests have already been developed to measure certain dimensions of a horse's temperament (fearfulness, gregariousness, etc.). In order to measure the temperament more precisely, our work aimed to identify a dimension which has already been described in several species but not yet in horses, namely sensory sensitivity. Our study was based on the definition of a temperament dimension as “a behavioural characteristic stable across situations and over time”. We designed several tests for each sense and then determined whether the responses observed were correlated between situations and in time. The principle of the tests was to generate two stimuli of different intensities for each sense (e.g. two different sounds) and to measure the intensity of the horse's response (N = 26). Using Spearman rank correlations, we tested whether the responses to these different stimuli were inter-correlated. We repeated the same tests 5 months later to determine whether the responses were correlated over time. Within each sense, results show that the greater the horses' response to one stimulus, the greater their response to the other. For example, the reaction to the odour of cinnamon (time spent near the source of the odour) was significantly correlated to the reaction to lavender (R = 0.53, p = 0.004). The reactions to two different sounds or to two different tactile stimuli (von Frey filaments, or contact of a brush on the body), were also significantly correlated (R = 0.59, p < 0.0001; R = 0.38, p = 0.029). Finally, the reactions to two different tastes or to two visual stimuli tended to be correlated (R = 0.27, p = 0.09; R = 0.27, p = 0.09). However, there was no significant correlation between the responses to stimuli relating to different senses. Finally, except for the responses to odour, the responses to other sensory stimuli showed stability over a 5-month period (e.g. tactile stimulation: R = 0.71, p < 0.0001). In conclusion, our study revealed characteristics which were stable across situations and over time. The absence of links between the characteristics measured for the different senses suggests that a dimension for each sense exists (e.g. tactile sensitivity) rather than a general sensory sensitivity dimension covering all the senses. |
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0168-1591 |
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Equine Behaviour @ team @ |
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4779 |
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Rørvang, M.V.; Nielsen, B.L.; McLean, A.N. |
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Title |
Sensory Abilities of Horses and Their Importance for Equitation Science |
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Journal Article |
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2020 |
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Frontiers in Veterinary Science |
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7 |
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633 |
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Vision, hearing, olfaction, taste, and touch comprise the sensory modalities of most vertebrates. With these senses, the animal receives information about its environment. How this information is organized, interpreted, and experienced is known as perception. The study of the sensory abilities of animals and their implications for behavior is central not only to ethology but also to animal welfare. Sensory ability, perception, and behavior are closely linked. Horses and humans share the five most common sensory modalities, however, their ranges and capacities differ, so that horses are unlikely to perceive their surroundings in a similar manner to humans. Understanding equine perceptual abilities and their differences is important when horses and human interact, as these abilities are pivotal for the response of the horse to any changes in its surroundings. This review aims to provide an overview of the current knowledge on the sensory abilities of horses. The information is discussed within an evolutionary context and also includes a practical perspective, outlining potential ways to mitigate risks of injuries and enhance positive horse-human interactions. The equine sensory apparatus includes panoramic visual capacities with acuities similar to those of red-green color-blind humans as well as aural abilities that, in some respects exceed human hearing and a highly developed sense of smell, all of which influence how horses react in various situations. Equine sensitivity to touch has been studied surprisingly sparingly despite tactile stimulation being the major interface of horse training. We discuss the potential use of sensory enrichment/positive sensory stimulation to improve the welfare of horses in various situations e.g. using odors, touch or sound to enrich the environment or to appease horses. In addition, equine perception is affected by factors such as breed, individuality, age, and in some cases even color, emphasizing that different horses may need different types of management. Understanding the sensory abilities of horses is central to the emerging discipline of equitation science, which comprises the gamut of horse-human interactions. Therefore, sensory abilities continue to warrant scientific focus, with more research to enable us to understand different horses and their various needs. |
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2297-1769 |
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Equine Behaviour @ team @ |
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6634 |
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Hauser, M.D.; Kralik, J.; Botto-Mahan, C.; Garrett, M.; Oser, J. |
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Self-recognition in primates: phylogeny and the salience of species-typical features |
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Journal Article |
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1995 |
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Proceedings of the National Academy of Sciences of the United States of America |
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Proc. Natl. Acad. Sci. U.S.A. |
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92 |
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23 |
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10811-10814 |
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Animals; *Behavior, Animal; *Cognition; Discrimination (Psychology); Exploratory Behavior; Female; Hair Color; Male; Phylogeny; Psychology, Comparative; Research Design; Saguinus/*psychology; *Self Concept; Species Specificity; Touch; *Visual Perception |
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Self-recognition has been explored in nonlinguistic organisms by recording whether individuals touch a dye-marked area on visually inaccessible parts of their face while looking in a mirror or inspect parts of their body while using the mirror's reflection. Only chimpanzees, gorillas, orangutans, and humans over the age of approximately 2 years consistently evidence self-directed mirror-guided behavior without experimenter training. To evaluate the inferred phylogenetic gap between hominoids and other animals, a modified dye-mark test was conducted with cotton-top tamarins (Saguinus oedipus), a New World monkey species. The white hair on the tamarins' head was color-dyed, thereby significantly altering a visually distinctive species-typical feature. Only individuals with dyed hair and prior mirror exposure touched their head while looking in the mirror. They looked longer in the mirror than controls, and some individuals used the mirror to observe visually inaccessible body parts. Prior failures to pass the mirror test may have been due to methodological problems, rather than to phylogenetic differences in the capacity for self-recognition. Specifically, an individual's sensitivity to experimentally modified parts of its body may depend crucially on the relative saliency of the modified part (e.g., face versus hair). Moreover, and in contrast to previous claims, we suggest that the mirror test may not be sufficient for assessing the concept of self or mental state attribution in nonlinguistic organisms. |
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Department of Anthropology, Harvard University, Cambridge, MA 02138, USA |
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0027-8424 |
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PMID:7479889 |
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Equine Behaviour @ team @ |
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2825 |
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Plotnik, J.M.; de Waal, F.B.M.; Reiss, D. |
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Self-recognition in an Asian elephant |
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Journal Article |
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2006 |
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Proceedings of the National Academy of Sciences of the United States of America |
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Proc. Natl. Acad. Sci. U.S.A. |
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103 |
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45 |
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17053-17057 |
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Animals; Asia; *Behavior, Animal; Cognition; Elephants/*psychology; Female; Photic Stimulation |
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Considered an indicator of self-awareness, mirror self-recognition (MSR) has long seemed limited to humans and apes. In both phylogeny and human ontogeny, MSR is thought to correlate with higher forms of empathy and altruistic behavior. Apart from humans and apes, dolphins and elephants are also known for such capacities. After the recent discovery of MSR in dolphins (Tursiops truncatus), elephants thus were the next logical candidate species. We exposed three Asian elephants (Elephas maximus) to a large mirror to investigate their responses. Animals that possess MSR typically progress through four stages of behavior when facing a mirror: (i) social responses, (ii) physical inspection (e.g., looking behind the mirror), (iii) repetitive mirror-testing behavior, and (iv) realization of seeing themselves. Visible marks and invisible sham-marks were applied to the elephants' heads to test whether they would pass the litmus “mark test” for MSR in which an individual spontaneously uses a mirror to touch an otherwise imperceptible mark on its own body. Here, we report a successful MSR elephant study and report striking parallels in the progression of responses to mirrors among apes, dolphins, and elephants. These parallels suggest convergent cognitive evolution most likely related to complex sociality and cooperation. |
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Living Links, Yerkes National Primate Research Center, and Department of Psychology, Emory University, 532 North Kligo Circle, Atlanta, GA 30322, USA |
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0027-8424 |
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PMID:17075063 |
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refbase @ user @ |
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408 |
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Author |
Scheffer, M.; van Nes, E.H. |
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Self-organized similarity, the evolutionary emergence of groups of similar species |
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Journal Article |
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2006 |
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Proceedings of the National Academy of Sciences of the United States of America |
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Proc. Natl. Acad. Sci. U.S.A. |
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103 |
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16 |
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6230-6235 |
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Animals; *Competitive Behavior; *Ecosystem; *Evolution; *Models, Biological |
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Ecologists have long been puzzled by the fact that there are so many similar species in nature. Here we show that self-organized clusters of look-a-likes may emerge spontaneously from coevolution of competitors. The explanation is that there are two alternative ways to survive together: being sufficiently different or being sufficiently similar. Using a model based on classical competition theory, we demonstrate a tendency for evolutionary emergence of regularly spaced lumps of similar species along a niche axis. Indeed, such lumpy patterns are commonly observed in size distributions of organisms ranging from algae, zooplankton, and beetles to birds and mammals, and could not be well explained by earlier theory. Our results suggest that these patterns may represent self-constructed niches emerging from competitive interactions. A corollary of our findings is that, whereas in species-poor communities sympatric speciation and invasion of open niches is possible, species-saturated communities may be characterized by convergent evolution and invasion by look-a-likes. |
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Aquatic Ecology and Water Quality Management Group, Department of Environmental Sciences, Wageningen University, P.O. Box 8080, 6700 DD, Wageningen, The Netherlands. marten.scheffer@wur.nl |
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English |
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0027-8424 |
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PMID:16585519 |
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refbase @ user @ |
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510 |
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Author |
Crowell-Davis, S.L. |
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Title |
Self-grooming by mares and foals of the Welsh pony (Equus caballus) |
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Year |
1987 |
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Applied Animal Behaviour Science |
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Appl. Anim. Behav. Sci. |
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17 |
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3-4 |
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197-208 |
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Abstract |
Self-grooming behaviour of 15 mare-foal pairs was studied weekly for the first 24 weeks of the foal's life. Mares self-groomed at mean rates of 1.2-2.2 times h-1 depending on the 4-week period. Foals self-groomed more often, with a peak rate of 12.3 times h-1 occurring during Week 5-8 and a subsequent decline to 6.0 times h-1 by Weeks 21-24. Self-grooming bouts of mares and foals also differed in the proportion devoted to each type of self-grooming. During a greater proportion of their total self-grooming bouts, foals scratched their head and neck with a hind limb or bit and scratched the trunk or hind limbs with the teeth. The mares spent a greater proportion of their self-grooming bouts rubbing their head or neck on an inanimate object, another pony, or their fore limb, or rolling on the ground. Particular types of individual self-grooming bouts were engaged in for different lengths of time. Foals had longer bouts of scratching the head and neck with a hind limb, scratching or biting the fore limb or hind limb with the teeth, and rubbing the head and neck on an inanimate object, while mares had longer bouts of rolling. Some of the differences in preference for particular types of self-grooming may be the result of differences in relative size of various body parts and, consequently, relative ease of a given type of self-grooming. |
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Equine Behaviour @ team @ |
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2275 |
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