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| Author | Povinelli DJ; Dunphy-Lelii S | ||||
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Do chimpanzees seek explanations? Preliminary comparative investigations | Type | Journal Article | ||
| Year | 2001 | Publication | Can. J. Exp. Psychol. | Abbreviated Journal | |
| Volume | 55 | Issue | Pages | 185 | |
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| Notes | Approved | no | |||
| Call Number | Equine Behaviour @ team @ | Serial | 3071 | ||
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| Author | Ushitani, T.; Fujita, K.; Yamanaka, R. | ||||
| Title |
Do pigeons (Columba livia) perceive object unity? | Type | Journal Article | ||
| Year | 2001 | Publication | Animal Cognition | Abbreviated Journal | Anim. Cogn. |
| Volume | 4 | Issue | 3 | Pages | 153-161 |
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| Abstract | Human infants perceive two rods moving in concert behind an occluder as one unitary rod. In four experiments we tested whether pigeons also perceive unity of objects. Pigeons were trained on a matching-to-sample task to discriminate between one unitary rod moving at a constant speed and two aligned rods moving together at the same speed. The latter stimulus was identical to the former except for a gap in the center. In experiment 1, we tested pigeons in probe trials in which a rectangle occluded the center of the sample rods, to see which comparison stimulus, the unitary rod or the aligned two rods, the subjects would match to the sample. Two of the three subjects pecked at the two rods significantly more often than at the unitary rod. In experiment 2, we trained the same pigeons to match the sample rods moving “in front of” the occluder. Pigeons persisted in matching two separate rods to the unitary rod moving in front of the occluder. In experiments 3 and 4, we used a parallelogram and an undulating shape as the occluder to alter the shape and the size of the portions above and below the occluder by the motion of the sample rods. Both subjects chose the two rods significantly more often than chance in experiment 3 and one of them did so in experiment 4. The results suggest that pigeons do not complete occluded portions even though the two elements move in concert. These negative results suggest that some alternative way of identifying objects may have evolved in pigeons. | ||||
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| Call Number | Equine Behaviour @ team @ | Serial | 3311 | ||
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| Author | Tebbich, S.; Taborsky, M.; Fessl, B.; Blomqvist, D. | ||||
| Title |
Do woodpecker finches acquire tool-use by social learning? | Type | Journal Article | ||
| Year | 2001 | Publication | Proceedings of the Royal Society of London B: Biological Sciences | Abbreviated Journal | Proc. Roy. Soc. Lond. B Biol. Sci. |
| Volume | 268 | Issue | 1482 | Pages | 2189-2193 |
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| Abstract | Tool–use is widespread among animals, but except in primates the development of this behaviour is poorly known. Here, we report on the first experimental study to our knowledge of the mechanisms underlying the acquisition of tool–use in a bird species. The woodpecker finch Cactospiza pallida, endemic to the Galápagos Islands, is a famous textbook example of tool–use in animals. This species uses modified twigs or cactus spines to pry arthropods out of tree holes. Using nestlings and adult birds from the field, we tested experimentally whether woodpecker finches learn tool–use socially. We show that social learning is not essential for the development of tool–use: all juveniles developed tool–use regardless of whether or not they had a tool–using model. However, we found that not all adult woodpecker finches used tools in our experiments. These non–tool–using individuals also did not learn this task by observing tool–using conspecifics. Our results suggest that tool–use behaviour depends on a very specific learning disposition that involves trial–and–error learning during a sensitive phase early in ontogeny. | ||||
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| Call Number | Equine Behaviour @ team @ | Serial | 5914 | ||
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| Author | Cook, R.G.; Shaw, R.; Blaisdell, A.P. | ||||
| Title |
Dynamic object perception by pigeons: discrimination of action in video presentations | Type | Journal Article | ||
| Year | 2001 | Publication | Animal Cognition | Abbreviated Journal | Anim. Cogn. |
| Volume | 4 | Issue | 3 | Pages | 137-146 |
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| Abstract | Two experiments examined the discrimination by pigeons of relative motion using computer-generated video stimuli. Using a go/no-go procedure, pigeons were tested with video stimuli in which the camera's perspective went either “around” or “through” an approaching object in a semi-realistic context. Experiment 1 found that pigeons could learn this discrimination and transfer it to videos composed from novel objects. Experiment 2 found that the order of the video's frames was critical to the discrimination of the videos. We hypothesize that the pigeons perceived a three-dimensional representation of the objects and the camera's relative motion and used this as the primary basis for discrimination. It is proposed that the pigeons might be able to form generalized natural categories for the different kinds of motions portrayed in the videos. | ||||
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| Notes | Approved | no | |||
| Call Number | Equine Behaviour @ team @ | Serial | 3142 | ||
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| Author | Gibbs, P.G.; Cohen, N.D. | ||||
| Title |
Early management of race-bred weanlings and yearlings on farms | Type | Journal Article | ||
| Year | 2001 | Publication | Journal of Equine Veterinary Science | Abbreviated Journal | J. Equine Vet. Sci. |
| Volume | 21 | Issue | 6 | Pages | 279-283 |
| Keywords | Equine, management, growth, nutrition, marketing | ||||
| Abstract | A total of 58 Thoroughbred and Quarter Horse farms that managed 1,987 weanlings and yearlings responded to a survey designed to better characterize early management of racing prospects. Average age at weaning was 5.5 months and over half of all farms kept almost three-fourths of all weanlings to be placed in pre-race training. Variation in feeding practices was evident and while well over half of all farms provided balanced nutrient supply to young horses, 20% to 40% likely fed unbalanced diets. An obvious preference existed for semi-confinement in young horses with plenty of free exercise. The majority of farms reported that young prospects were fed and managed for a moderate rate of growth. Forced exercise occurred to a much larger extent with yearlings than weanlings and 40% of farms described the footing as soft, but not deep. Response to the prevalence of developmental orthopedic diseases appeared somewhat guarded, and average injury rate was low on farms that attributed much of injury to horses playing too hard. Technological advancements such as photoperiod manipulation in broodmares were widely used, while valuable tools such as body condition scoring were utilized to a lesser extent. |
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| Notes | Approved | no | |||
| Call Number | Equine Behaviour @ team @ | Serial | 5758 | ||
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| Author | Johnstone, R.A. | ||||
| Title |
Eavesdropping and animal conflict | Type | Journal Article | ||
| Year | 2001 | Publication | Proceedings of the National Academy of Sciences of the United States of America | Abbreviated Journal | Proc. Natl. Acad. Sci. U.S.A. |
| Volume | 98 | Issue | 16 | Pages | 9177-9180 |
| Keywords | *Aggression; Animals; *Behavior, Animal; *Conflict (Psychology); Models, Theoretical | ||||
| Abstract | Fights between pairs of animals frequently take place within a wider social context. The displays exchanged during conflict, and the outcome of an encounter, are often detectable by individuals who are not immediately involved. In at least some species, such bystanders are known to eavesdrop on contests between others, and to modify their behavior toward the contestants in response to the observed interaction. Here, I extend Maynard Smith's well known model of animal aggression, the Hawk-Dove game, to incorporate the possibility of eavesdroppers. I show that some eavesdropping is favored whenever the cost of losing an escalated fight exceeds the value of the contested resource, and that its equilibrium frequency is greatest when costs are relatively high. Eavesdropping reduces the risk of escalated conflict relative to that expected by chance, given the level of aggression in the population. However, it also promotes increased aggression, because it enhances the value of victory. The net result is that escalated conflicts are predicted to occur more frequently when eavesdropping is possible. | ||||
| Address | Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, United Kingdom. raj1003@hermes.cam.ac.uk | ||||
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| Language | English | Summary Language | Original Title | ||
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| ISSN | 0027-8424 | ISBN | Medium | ||
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| Notes | PMID:11459936 | Approved | no | ||
| Call Number | refbase @ user @ | Serial | 497 | ||
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| Author | Feh, C.; Munkhtuya, B.; Enkhbold, S.; Sukhbaatar, T. | ||||
| Title |
Ecology and social structure of the Gobi khulan Equus hemionus subsp. in the Gobi B National Park, Mongolia | Type | Journal Article | ||
| Year | 2001 | Publication | Biological Conservation | Abbreviated Journal | Biol. Conserva. |
| Volume | 101 | Issue | 1 | Pages | 51-61 |
| Keywords | Equus hemionus; Ecology and social structure; Gobi National Park; Mongolia | ||||
| Abstract | The status of the Gobi khulan Equus hemionus subsp. is recorded as “insufficiently known” in the Species Survival Commission's Equid Action Plan. Recent counts confirm that Mongolia holds the most important population of the whole species. Since 1953, the animals have benefited from a protected status, but this is now challenged. A 5-year study in the B part of the Gobi National Park on one subpopulation showed that it has remained stable over the past 15 years with an adequate mean reproductive rate of 15% and a 50% survival rate over the first year. Age/sex related mortality and prey analysis indicate that wolf predation probably has some impact on the population, in particular for 4-6-year-olds of both sexes at the start of reproduction. Desert and mountain steppes are the khulan's year-round preferred habitat, but `oases', play an important role at the beginning of lactation. Anthropogenic factors affect both home range and habitat use through direct intervention or permanent occupation of the scarce water sources. Khulans of this subpopulation, unlike other Asian and African wild asses, form year-round stable, non-territorial families. These families and all-male groups join together into “bands” in winter, and herds of several hundred animals, where reproductive rate is highest, form throughout the year. The existence of such herds may thus be critical for the breeding success of the population. Our study provides the first detailed quantitative data for this subspecies, which will help to monitor changes in the future. | ||||
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| Notes | Approved | no | |||
| Call Number | Equine Behaviour @ team @ | Serial | 2289 | ||
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| Author | Malmgren, L.; Andresen, Ø.; Dalin, A.-M. | ||||
| Title |
Effect of GnRH immunisation on hormonal levels, sexual behaviour, semen quality and testicular morphology in mature stallions | Type | Journal Article | ||
| Year | 2001 | Publication | Equine Veterinary Journal | Abbreviated Journal | Equine vet. J. |
| Volume | 33 | Issue | 1 | Pages | 75-83 |
| Keywords | horse; GnRH; immunisation; stallion; testosterone; oestrone sulphate; sexual behaviour; semen quality | ||||
| Abstract | Summary The aim of this study was to investigate the effect of gonadotrophin-releasing hormone (GnRH) immunisation on mature stallions that had been used for breeding. Four Standardbred stallions were used in the study: 3 experimental animals and 1 control animal. Semen was collected regularly, i.e. twice/week, during the 4 months prior to the experimental period. The stallions were immunised against GnRH with a GnRH-BSA conjugate. Equimune was used as the adjuvant. The stallions were immunised on 5 occasions, 4 at 2 week intervals, and the fifth 4 weeks after the fourth. Blood samples were taken once a week for analysis of GnRH antibody titre and every third week for testosterone and oestrone sulphate analyses. Semen was collected once a week, and libido and sexual behaviour were observed. Ejaculate volume, sperm concentration, total number of sperm in the ejaculate, sperm motility and sperm morphology were evaluated. Testicular size was measured once a week. At the end of the study, the stallions were castrated, and a histological examination of the testes performed. All immunised stallions produced antibodies against GnRH, and plasma testosterone concentration decreased. However, the effect of immunisation varied between stallions. In 2 of the stallions, high levels of antibodies were found, while in the third, the level was moderate. Four weeks after the first immunisation, a decrease in libido was observed. Two months after the first immunisation, marked changes in semen quality were observed in the 2 stallions with high antibody titres. Fourteen weeks after the first immunisation, the total number of sperm/ejaculate had decreased from >8.6×109 to<2.7×109, sperm motility from >59 to<10% and the frequency of morphological normal spermatozoa had decreased from >60 to<14%. The dominating abnormalities were abnormal head shapes, proximal cytoplasmic droplets and detached heads. In the third stallion, only slight changes in semen quality were found. No changes were observed in the control stallion. Decreases in testicular size were noted in all of the experimental stallions. Pronounced histological alterations in the testes were observed in 2 of the stallions. It is concluded that the vaccine was effective in stimulating production of GnRH antibodies and in suppressing testicular function and androgen secretion. However, there was an individual variation in the responses among the stallions and, further, libido was not totally suppressed. | ||||
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| Publisher | Blackwell Publishing Ltd | Place of Publication | Editor | ||
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| ISSN | 2042-3306 | ISBN | Medium | ||
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| Notes | Approved | no | |||
| Call Number | Equine Behaviour @ team @ | Serial | 5312 | ||
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| Author | Nyman, S.; Dahlborn, K. | ||||
| Title |
Effect of water supply method and flow rate on drinking behavior and fluid balance in horses | Type | Journal Article | ||
| Year | 2001 | Publication | Physiology & Behavior | Abbreviated Journal | Physiol. Behav. |
| Volume | 73 | Issue | 1-2 | Pages | 1-8 |
| Keywords | Animals; Choice Behavior/physiology; Drinking Behavior/*physiology; Horses/*physiology; Male; Thirst/physiology; *Water Supply; Water-Electrolyte Balance/*physiology | ||||
| Abstract | This study investigated three methods of water supply on drinking preference and behavior in six Standardbred geldings (2-9 years, 505+/-9 kg). The water sources were buckets (B), pressure valve (PV), and float valve (FV) bowls. In an initial drinking preference test, PV was tested at three flow rates: 3, 8, and 16 l/min (PV3, PV8, and PV16), and FV at 3 l/min (FV3). Water intake was measured in l and presented as the percentage of the total daily water intake from each of two simultaneously presented alternatives. The intake from PV8 was greater than from both PV3 (72+/-11% vs. 28+/-11%) and PV16 (90+/-4% vs. 10+/-4%). All horses showed a strong preference for B, 98+/-1% of the intake compared to 2+/-1% from PV8. Individual variation in the data gave no significant difference in preference between the two automatic bowls. In the second part of the study, drinking behavior and fluid balance were investigated when the horses drank from FV3, PV8, and B for 7 consecutive days in a changeover design. Despite a tendency for an increase in total daily drinking time from FV3, the daily water intake was significantly lower (43+/-3 ml/kg) than from PV8 (54+/-2 ml/kg) and B (58+/-3 ml/kg). Daily net water gain [intake-(fecal+urinary output)] was only 0.5+/-3 ml/kg with FV3, resulting in a negative fluid balance if insensible losses are included. These results show that the water supply method can affect both drinking behavior and fluid balance in the horse. | ||||
| Address | Department of Animal Physiology, Swedish University of Agricultural Sciences, Box 7045, S-750 07 Uppsala, Sweden. sara.nyman@djfys.slu.se | ||||
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| Language | English | Summary Language | Original Title | ||
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| ISSN | 0031-9384 | ISBN | Medium | ||
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| Notes | PMID:11399288 | Approved | no | ||
| Call Number | refbase @ user @ | Serial | 1919 | ||
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| Author | Fagot, J.; Tomonaga, M. | ||||
| Title |
Effects of element separation on perceptual grouping by humans (Homo sapiens) and chimpanzees (Pan troglodytes): perception of Kanizsa illusory figures | Type | Journal Article | ||
| Year | 2001 | Publication | Animal Cognition | Abbreviated Journal | Anim. Cogn. |
| Volume | 4 | Issue | 3 | Pages | 171-177 |
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| Abstract | The processing of Kanizsa-square illusory figures was studied in two experiments with four humans and two chimpanzees. Subjects of the two species were initially trained to select a Kanizsa-square illusory figure presented in a computerized two-alternative forced choice task. After training, adding narrow closing segments to the pacman inducers that composed the Kanisza illusory figures lowered performance in both chimpanzees and humans, suggesting that the discrimination could be controlled by the perception of illusory forms. A second experiment assessed transfer of performance with five sets of figures in which the size of the inducers and their separation were manipulated. Only for chimpanzees was performance directly controlled by separation, suggesting that chimpanzees are more sensitive than humans to the separation between visual elements. | ||||
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| Call Number | Equine Behaviour @ team @ | Serial | 3172 | ||
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