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Hampton, R. R., & Shettleworth, S. J. (1996). Hippocampal lesions impair memory for location but not color in passerine birds. Behav Neurosci, 110(4), 831–835.
Abstract: The effects of hippocampal complex lesions on memory for location and color were assessed in black-capped chickadees (Parus atricapillus) and dark-eyed juncos (Junco hyemalis) in operant tests of matching to sample. Before surgery, most birds were more accurate on tests of memory for location than on tests of memory for color. Damage to the hippocampal complex caused a decline in memory for location, whereas memory for color was not affected in the same birds. This dissociation indicates that the avian hippocampus plays an important role in spatial cognition and suggests that this brain structure may play no role in working memory generally.
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Verdolin, J. (2009). Gunnison’s prairie dog (Cynomys gunnisoni): testing the resource dispersion hypothesis. Beh. Ecol. Sociobiol., 63(6), 789–799.
Abstract: Few studies have experimentally tested the resource dispersion hypothesis (RDH). In this study, I tested whether space use and social organization of Gunnison’s prairie dog responded to changes in the dispersion and abundance of resources. Food manipulations were carried out during the reproductive and nonreproductive seasons across 2 years. Gunnison’s prairie dog adults responded to the experiments by decreasing territory size as food became patchier in space and time. Both males and females modified their home ranges, with no detectable difference between sexes, either prior to or during the experiments. As food became patchier in space and time, the spatial overlap of adults increased, whereas it decreased as food became more evenly dispersed. The average size of a group, defined as those individuals occupying the same territory, did not change significantly as a result of the experiments. Where changes in the composition and size of groups did occur, there was no indication that such changes were sex specific. Results from this study support critical components of the RDH and strongly suggest that patterns of space use and social structure in Gunnison’s prairie dogs are the result of individual responses to resource abundance and distribution.
Keywords: Biomedical and Life Sciences
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Choleris, E., & Kavaliers, M. (1999). Social Learning in Animals: Sex Differences and Neurobiological Analysis. Pharmacol. Biochem. Behav., 64(4), 767–776.
Abstract: Social learning where an “individual's behavior is influenced by observation of, or interaction with, another animal or its products” has been extensively documented in a broad variety of species, including humans. Social learning occurs within the complex framework of an animal's social interactions that are markedly affected by factors such as dominance hierarchies, family bonds, age, and sex of the interacting individuals. Moreover, it is clear that social learning is influenced not only by important sexually dimorphic social constraints but also that it involves attention, motivational, and perceptual mechanisms, all of which exhibit substantial male-female differences. Although sex differences have been demonstrated in a wide range of cognitive and behavioral processes, investigations of male-female differences in social learning and its neurobiological substrates have been largely neglected. As such, sex differences in social learning and its neurobiological substrates merit increased attention. This review briefly considers various aspects of the study of social learning in mammals, and indicates where male-female differences have either been described, neglected and, or could have a potential impact. It also describes the results of neurobiological investigations of social learning and considers the relevance of these findings to other sexually dimorphic cognitive processes.
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Whitehead, H. (2009). SOCPROG programs: analysing animal social structures. Behav. Ecol. Sociobiol., 63(5), 765–778.
Abstract: Abstract SOCPROG is a set of programs which analyses data on animal associations. Data usually come from observations of the social behaviour of individually identifiable animals. Associations among animals, sampling periods, restrictions on the data and association indices can be defined very flexibly. SOCPROG can analyse data sets including 1,000 or more individuals. Association matrices are displayed using sociograms, principal coordinates analysis, multidimensional scaling and cluster analyses. Permutation tests, Mantel and related tests and matrix correlation methods examine hypotheses about preferred associations among individuals and classes of individual. Weighted network statistics are calculated and can be tested against null hypotheses. Temporal analyses include displays of lagged association rates (rates of reassociation following an association). Models can be fitted to lagged association rates. Multiple association measures, including measures produced by other programs such as genetic or range use data, may be analysed using Mantel tests and principal components analysis. SOCPROG also performs mark-recapture population analyses and movement analyses. SOCPROG is written in the programming language MATLAB and may be downloaded free from the World Wide Web.
Keywords: Social analysis – Software – Association
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Griffiths, D. P., & Clayton, N. S. (2001). Testing episodic memory in animals: A new approach. Physiol. Behav., 73(5), 755–762.
Abstract: Episodic memory involves the encoding and storage of memories concerned with unique personal experiences and their subsequent recall, and it has long been the subject of intensive investigation in humans. According to Tulving's classical definition, episodic memory “receives and stores information about temporally dated episodes or events and temporal-spatial relations among these events.” Thus, episodic memory provides information about the `what' and `when' of events (`temporally dated experiences') and about `where' they happened (`temporal-spatial relations'). The storage and subsequent recall of this episodic information was thought to be beyond the memory capabilities of nonhuman animals. Although there are many laboratory procedures for investigating memory for discrete past episodes, until recently there were no previous studies that fully satisfied the criteria of Tulving's definition: they can all be explained in much simpler terms than episodic memory. However, current studies of memory for cache sites in food-storing jays provide an ethologically valid model for testing episodic-like memory in animals, thereby bridging the gap between human and animal studies memory. There is now a pressing need to adapt these experimental tests of episodic memory for other animals. Given the potential power of transgenic and knock-out procedures for investigating the genetic and molecular bases of learning and memory in laboratory rodents, not to mention the wealth of knowledge about the neuroanatomy and neurophysiology of the rodent hippocampus (a brain area heavily implicated in episodic memory), an obvious next step is to develop a rodent model of episodic-like memory based on the food-storing bird paradigm. The development of a rodent model system could make an important contribution to our understanding of the neural, molecular, and behavioral mechanisms of mammalian episodic memory.
Keywords: Episodic memory; Food-caching; Animal models
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Fischhoff, I. R., Sundaresan, S. R., Cordingley, J., & Rubenstein, D. I. (2007). Habitat use and movements of plains zebra (Equus burchelli) in response to predation danger from lions. Behav. Ecol., 18(4), 725–729.
Abstract: Prey species must adapt their behavior to avoid predation. As a key prey item for lions (Panthera leo), plains zebras (Equus burchelli) were expected to respond to immediate threats posed by lions in their area. In addition, zebras were predicted to exhibit behavior tuned to reduce the potential for encounters with lions, by modifying their movement patterns in the times of day and habitats of greatest lion danger. We studied a population of approximately 600 plains zebra living in Ol Pejeta Conservancy, Kenya. We found that zebra abundance on or near a grassland patch was lower if lions had also been observed on that patch during the same day. Predation danger was highest in grassland habitat during the night, when lions were more active. Zebra sightings and global positioning system radio collar data indicated that zebras also reduced their use of grassland at night, instead using more woodland habitat. Zebras moved faster and took sharper turns in grassland at night. It is hypothesized that these more erratic movements assist zebras in avoiding detection or capture by lions.
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Cant, M. A., & Field, J. (2005). Helping effort in a dominance hierarchy. Behav. Ecol., 16(4), 708–715.
Abstract: In many cooperatively breeding species, group members form a dominance hierarchy or queue to inherit the position of breeder. Models aimed at understanding individual variation in helping behavior, however, rarely take into account the effect of dominance rank on expected future reproductive success and thus the potential direct fitness costs of helping. Here we develop a kin-selection model of helping behavior in multimember groups in which only the highest ranking individual breeds. Each group member can invest in the dominant's offspring at a cost to its own survivorship. The model predicts that lower ranked subordinates, who have a smaller probability of inheriting the group, should work harder than higher ranked subordinates. This prediction holds regardless of whether the intrinsic mortality rate of subordinates increases or decreases with rank. The prediction does not necessarily hold, however, where the costs of helping are higher for lower ranked individuals: a situation that may be common in vertebrates. The model makes two further testable predictions: that the helping effort of an individual of given rank should be lower in larger groups, and the reproductive success of dominants should be greater where group members are more closely related. Empirical evidence for these predictions is discussed. We argue that the effects of rank on stable helping effort may explain why attempts to correlate individual helping effort with relatedness in cooperatively breeding species have met with limited success.
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Byrne, R. W. (1993). Do larger brains mean greater intelligence? Behav. Brain Sci., 16(4), 696–697. |
Milgram, N. W., Head, E., Muggenburg, B., Holowachuk, D., Murphey, H., Estrada, J., et al. (2002). Landmark discrimination learning in the dog: effects of age, an antioxidant fortified food, and cognitive strategy. Neurosci Biobehav Rev, 26(6), 679–695.
Abstract: The landmark discrimination learning test can be used to assess the ability to utilize allocentric spatial information to locate targets. The present experiments examined the role of various factors on performance of a landmark discrimination learning task in beagle dogs. Experiments 1 and 2 looked at the effects of age and food composition. Experiments 3 and 4 were aimed at characterizing the cognitive strategies used in performance on this task and in long-term retention. Cognitively equivalent groups of old and young dogs were placed into either a test group maintained on food enriched with a broad-spectrum of antioxidants and mitochondrial cofactors, or a control group maintained on a complete and balanced food formulated for adult dogs. Following a wash-in period, the dogs were tested on a series of problems, in which reward was obtained when the animal responded selectively to the object closest to a thin wooden block, which served as a landmark. In Experiment 1, dogs were first trained to respond to a landmark placed directly on top of coaster, landmark 0 (L0). In the next phase of testing, the landmark was moved at successively greater distances (1, 4 or 10 cm) away from the reward object. Learning varied as a function of age group, food group, and task. The young dogs learned all of the tasks more quickly than the old dogs. The aged dogs on the enriched food learned L0 significantly more rapidly than aged dogs on control food. A higher proportion of dogs on the enriched food learned the task, when the distance was increased to 1cm. Experiment 2 showed that accuracy decreased with increased distance between the reward object and landmark, and this effect was greater in old animals. Experiment 3 showed stability of performance, despite using a novel landmark, and new locations, indicating that dogs learned the landmark concept. Experiment 4 found age impaired long-term retention of the landmark task. These results indicate that allocentric spatial learning is impaired in an age-dependent manner in dogs, and that age also affects performance when the distance between the landmark and target is increased. In addition, these results both support a role of oxidative damage in the development of age-associated cognitive dysfunction and indicate that short-term administration of a food enriched with supplemental antioxidants and mitochondrial cofactors can partially reverse the deleterious effects of aging on cognition.
Keywords: Age Factors; Aging/*physiology; Analysis of Variance; Animals; Antioxidants/*pharmacology; Blood Chemical Analysis/methods; Cognition/*physiology; *Diet; Discrimination Learning/*drug effects/*physiology; Distance Perception/drug effects/physiology; Dogs/physiology; Female; Male; Psychomotor Performance/physiology; Retention (Psychology)/drug effects/physiology; Spatial Behavior/*drug effects/*physiology; Task Performance and Analysis; Time Factors; Vitamin E/blood
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Taillon, J., & Côté, S. (2008). Are faecal hormone levels linked to winter progression, diet quality and social rank in young ungulates ? An experiment with white-tailed deer ( Odocoileus virginianus ) fawns. Behav. Ecol. Sociobiol., 62(10), 675–677.
Abstract: Abstract Hormones play a central role in the physiology and behaviour of animals. The recent development of noninvasive techniques has increased information on physical and social states of individuals through hormone measurements. The relationships among hormones, life history traits and behaviours are, however, still poorly known. For the first time, we evaluated natural winter glucocorticoid and testosterone levels in young ungulates in relation to winter progression, diet quality and social rank. Overwinter, levels of glucocorticoid and testosterone decreased, possibly due to the decline of fawns" body mass. The relationships between hormone levels and diet quality were surprising: Fawns fed the control diet presented higher glucocorticoid and lower testosterone levels then fawns fed the poor diet, suggesting that control fawns faced a higher nutritional stress than those on the poor diet. Similarly to other studies on social mammals, we found no relationship between faecal glucocorticoid levels and social rank, suggesting that social stress was similar for dominant and subordinate fawns during winter. Testosterone levels were not correlated to social rank as found previously in groups of individuals forming stable social hierarchies and maintaining stable dominance relationships. The simultaneous suppression of glucocorticoid and testosterone levels suggests for the first time that young ungulates present a hormonal strategy to prevent fast depletion of limited proteins and fat resources during winter.
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