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Kiltie, R. A., Fan, J., & Laine, A. F. (1995). A wavelet-based metric for visual texture discrimination with applications in evolutionary ecology. Math Biosci, 126(1), 21–39.
Abstract: Much work on natural and sexual selection is concerned with the conspicuousness of visual patterns (textures) on animal and plant surfaces. Previous attempts by evolutionary biologists to quantify apparency of such textures have involved subjective estimates of conspicuousness or statistical analyses based on transect samples. We present a method based on wavelet analysis that avoids subjectivity and that uses more of the information in image textures than transects do. Like the human visual system for texture discrimination, and probably like that of other vertebrates, this method is based on localized analysis of orientation and frequency components of the patterns composing visual textures. As examples of the metric's utility, we present analyses of crypsis for tigers, zebras, and peppered moth morphs.
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Boysen, S. T., & Berntson, G. G. (1995). Responses to quantity: perceptual versus cognitive mechanisms in chimpanzees (Pan troglodytes). J Exp Psychol Anim Behav Process, 21(1), 82–86.
Abstract: Two chimpanzees were trained to select among 2 different amounts of candy (1-6 items). The task was designed so that selection of either array by the active (selector) chimpanzee resulted in that array being given to the passive (observer) animal, with the remaining (nonselected) array going to the selector. Neither animal was able to select consistently the smaller array, which would reap the larger reward. Rather, both animals preferentially selected the larger array, thereby receiving the smaller number of reinforcers. When Arabic numerals were substituted for the food arrays, however, the selector animal evidenced more optimal performance, immediately selecting the smaller numeral and thus receiving the larger reward. These findings suggest that a basic predisposition to respond to the perceptual-motivational features of incentive stimuli can interfere with task performance and that this interference can be overridden when abstract symbols serve as choice stimuli.
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Koenen, E. P. C., van Veldhuizen, A. E., & Brascamp, E. W. (1995). Genetic parameters of linear scored conformation traits and their relation to dressage and show-jumping performance in the Dutch Warmblood Riding Horse population. Livestock Production Science, 43(1), 85–94.
Abstract: In this study genetic parameters of linear scored conformation traits of the Dutch Warmblood Riding Horse were estimated in relation to performance in competition. Observations on 10 665 mares were analyzed with an animal model including the fixed effects age, classifier, location and percentage of thoroughbred. Using restricted maximum likelihood algorithms, heritabilities of 26 linear scored conformation traits were estimated in the range 0.09-0.28. Several conformation traits had high up to very high mutual genetic correlations. Competition results of 3476 horses with performance in dressage and 3220 horses with performance in show-jumping were linked to the conformation data to estimate the genetic relationship between conformation and performance in competition. The model for the evaluation of the competition results included the fixed effects riding club, age and sex. Estimated heritabilities for dressage and show-jumping were 0.17 +/- 0.05 and 0.19 +/- 0.04, respectively. Genetic correlations between conformation and performance were low to moderate. The length of the neck, length and position of the shoulders, shape and length of croup and muscularity of the haunches had a significant moderate genetic correlation with dressage. Muscularity of the neck, shape of the croup and muscularity of the haunches had a significant genetic correlation with show-jumping. The results indicate that, due to the low genetic correlations with performance traits, indirect selection for performance using conformation results is of limited value.
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Kasuya, E. (1995). A randomization test for linearity of dominance hierarchies. J. Ethol., 13(1), 137–140.
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Russon, A. E., & Galdikas, B. M. F. (1995). Constraints on great apes' imitation: Model and action selectivity in rehabilitant orangutan (Pongo pygmaeus) imitation. J. Comp. Psychol., 109(1), 5–17.
Abstract: We discuss selectivity in great ape imitation, on the basis of an observational study of spontaneous imitation in free-ranging rehabilitant orangutans (Pongo pygmaeus). Research on great ape imitation has neglected selectivity, although comparative evidence suggests it may be important. We observed orangutans in central Indonesian Borneo and assessed patterns in the models and actions they spontaneously imitated. The patterns we found resembled those reported in humans. Orangutans preferred models with whom they had positive affective relationships (e.g., important caregiver or older sibling) and actions that reflected their current competence, were receptively familiar, and were relevant to tasks that faced them. Both developmental and individual variability were found. We discuss the probable functions of imitation for great apes and the role of selectivity in directing it. We also make suggestions for more effective elicitation of imitation. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
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i Rios, J. F., & Houpt, K. (1995). Sexual behavior in geldings. Appl. Anim. Behav. Sci., 46(1-2), 133–135.
Abstract: 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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Chalmeau, R., & Gallo, A. (1995). Cooperation in primates: Critical analysis of behavioural criteria. Behav. Process., 35(1-3), 101–111.
Abstract: Concerning hunting in chimpanzees, cooperation has generally been attributed to the behaviour of two or more individuals acting together to achieve a common goal (Boesch and Boesch, 1989). The common goal is often considered as the concrete result of a common action by two or several individuals. Although this result could be used as a criterion for cooperation, it could also be an outcome due to chance. We suggest that the goal, viewed as a concrete benefit shared by the partners, is not a requisite of cooperation but rather a possible consequence of a common action largely submitted to social constraints. Individuals engaged in a cooperative task in order to solve a problem have to exchange information to adjust to each other's behaviour. However, evidence of communication between partners during simultaneous cooperation is rare. An experiment in which two chimpanzees each had to simultaneously pull a handle to get a fruit was performed. We analysed not only the concrete result of the partners' activity but also what the individuals took into account before pulling a handle. We tried to specify what the chimpanzees learned by means of a series of logical propositions which we were able to confront the experimental results.
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Lefebvre, L. (1995). Ecological correlates of social learning: problems and solutions for the comparative method. Behav. Process., 35(1-3), 163–171.
Abstract: Interspecific variation in learning and cognition is often accounted for by adaptive specialization, an ecological framework where variation between species in the environmental problems they face is thought to select for quantitatively and/or qualitatively different abilities. Adaptive specialization theory relies on the comparative method for testing its hypotheses and assumes a naturally selected basis for the predicted differences. This review examines social learning as a specialization to group-living and scramble feeding competition. It points out one important problem with current studies in the area, the lack of quantitative controls for confounding variables that may cause type 1 or 2 error in comparative tests. A linear regression technique is proposed to measure and remove interspecific differences on control tests for which there is no predicted adaptive specialization; as in other areas of comparative biology, the adaptive prediction is then made on the residual deviation from the regression of these confounding variables. Examples are given from research on opportunistic Columbids, the group-living feral pigeon Columbia livia, and the territorial Zenaida dove, Zenaida aurita.
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Pere, M. C. (1995). Maternal and fetal blood levels of glucose, lactate, fructose, and insulin in the conscious pig. J. Anim Sci., 73(10), 2994–2999.
Abstract: To study nutrition and metabolism in the fetal pig, a chronic catheterization method was developed that allows blood sampling in arteries and veins, at both the umbilical and uterine sources, in the conscious, unstressed animal. A catheter was inserted in the fetal aorta through a femoral artery, and another one was introduced in the umbilical vein. A catheter was put in a femoral artery of the sow so that its end was in the abdominal aorta. A fourth catheter was placed in a uterine vein draining the fetoplacental unit studied. This procedure was applied to 18 Large White primiparous sows at 99 d of gestation. Blood samples were drawn simultaneously using the four catheters before a meal at 103 d of pregnancy, and glucose, insulin, lactate, and fructose were determinated. Glycemia was 2.5 times higher in the sow than in the fetus. The extraction coefficient of glucose by the fetus amounted to 14% of the umbilical supply. The insulin level in the fetal pig was very low ( < 5 microU/mL). Lactate and fructose seemed to originate from the placenta. Blood lactate was 2.6 times lower in the sow than in the fetus, and its extraction coefficient by the fetus amounted to 8%. Fructose in the fetal blood was 2.3 times higher than that of glucose. Fructose was not utilized by the pig fetus. The present results obtained in the fetal pig are comparable to the conclusions drawn from studies with other species.
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Krebs, J. R., Clayton, N. S., Hampton, R. R., & Shettleworth, S. J. (1995). Effects of photoperiod on food-storing and the hippocampus in birds. Neuroreport, 6(12), 1701–1704.
Abstract: Birds that store food have a relatively large hippocampus compared to non-storing species. The hippocampus shows seasonal differences in neurogenesis and volume in black-capped chikadees (Parus atricapillus) taken from the wild at different times of year. We compared hippocampal volumes in black-capped chickadees captured at the same time but differing in food-storing behaviour because of manipulations of photoperiod in the laboratory. Differences in food-storing behaviour were not accompanied by differences in the volume of the hippocampus. Hippocampal volumes also did not differ between two groups of a non-food-storing control species, house sparrows (Passer domesticus), exposed to the same conditions as the chickadees.
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