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Imura, T., & Tomonaga, M. (2003). Perception of depth from shading in infant chimpanzees ( Pan troglodytes). Anim. Cogn., 6(4), 253–258.
Abstract: We investigated the ability to perceive depth from shading, one of the pictorial depth cues, in three chimpanzee infants aged 4-10 months old, using a preferential reaching task commonly used to study pictorial depth perception in human infants. The chimpanzee infants reached significantly more to three-dimensional toys than to pictures thereof and more to the three-dimensional convex than to the concave. Furthermore, two of the three infants reached significantly more to the photographic convex than to the photographic concave. These infants also looked longer at the photographic convex than the concave. Our results suggest that chimpanzees perceive, at least as early as the latter half of the first year of life, pictorial depth defined by shading information. Photographic convexes contain richer information about pictorial depth (e.g., attached shadow, cast shadow, highlighted area, and global difference in brightness) than simple computer-graphic graded patterns. These cues together might facilitate the infants' perception of depth from shading.
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Hirata, S., & Celli, M. L. (2003). Role of mothers in the acquisition of tool-use behaviours by captive infant chimpanzees. Anim. Cogn., 6(4), 235–244.
Abstract: This article explores the maternal role in the acquisition of tool-use behaviours by infant chimpanzees ( Pan troglodytes). A honey-fishing task, simulating ant/termite fishing found in the wild, was introduced to three dyads of experienced mother and naive infant chimpanzees. Four fishing sites and eight sets of 20 objects to be used as tools, not all appropriate, were available. Two of the mothers constantly performed the task, using primarily two kinds of tools; the three infants observed them. The infants, regardless of the amount of time spent observing, successfully performed the task around the age of 20-22 months, which is earlier than has been recorded in the wild. Two of the infants used the same types of tools that the adults predominantly used, suggesting that tool selectivity is transmitted. The results also show that adults are tolerant of infants, even if unrelated; infants were sometimes permitted to lick the tools, or were given the tools, usually without honey, as well as permitted to observe the adult performances closely.
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Sousa, C., Okamoto, S., & Matsuzawa, T. (2003). Behavioural development in a matching-to-sample task and token use by an infant chimpanzee reared by his mother. Anim. Cogn., 6(4), 259–267.
Abstract: We investigated the behavioural and cognitive development of a captive male infant chimpanzee, Ayumu, raised by his mother, Ai. Here we report Ayumu's achievements up to the age of 2 years and 3 months, in the context of complex computer-controlled tasks. From soon after birth, Ayumu had been present during an experiment performed by his mother. The task consisted of two phases, a matching-to-sample task in which she received token rewards, and the insertion of these tokens into a vending machine to obtain food rewards. Ayumu himself received no reward or encouragement from humans for any of the actions he exhibited during the experiment. At the age of 9 months and 3 weeks, Ayumu performed his first matching-to-sample trial. At around 1 year and 3 months, he began to perform them consistently. Also during this period, he frequently stole food rewards from his mother. At 2 years and 3 months, Ayumu succeeded for the first time in inserting a token into the vending machine. Once he had succeeded in using a token, he performed both phases of the task in sequence 20 times consecutively. The infant's behaviour was not shaped by food rewards but by a strong motivation to copy his mother's behaviour. Our observations of Ayumu thus mirror the learning processes shown by wild chimpanzees.
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Hayashi, M., & Matsuzawa, T. (2003). Cognitive development in object manipulation by infant chimpanzees. Anim. Cogn., 6(4), 225–233.
Abstract: This study focuses on the development of spontaneous object manipulation in three infant chimpanzees during their first 2 years of life. The three infants were raised by their biological mothers who lived among a group of chimpanzees. A human tester conducted a series of cognitive tests in a triadic situation where mothers collaborated with the researcher during the testing of the infants. Four tasks were presented, taken from normative studies of cognitive development of Japanese infants: inserting objects into corresponding holes in a box, seriating nesting cups, inserting variously shaped objects into corresponding holes in a template, and stacking up wooden blocks. The mothers had already acquired skills to perform these manipulation tasks. The infants were free to observe the mothers' manipulative behavior from immediately after birth. We focused on object-object combinations that were made spontaneously by the infant chimpanzees, without providing food reinforcement for any specific behavior that the infants performed. The three main findings can be summarized as follows. First, there was precocious appearance of object-object combination in infant chimpanzees: the age of onset (8-11 months) was comparable to that in humans (around 10 months old). Second, object-object combinations in chimpanzees remained at a low frequency between 11 and 16 months, then increased dramatically at the age of approximately 1.5 years. At the same time, the accuracy of these object-object combinations also increased. Third, chimpanzee infants showed inserting behavior frequently and from an early age but they did not exhibit stacking behavior during their first 2 years of life, in clear contrast to human data.
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Santos, L. R., Miller, C. T., & Hauser, M. D. (2003). Representing tools: how two non-human primate species distinguish between the functionally relevant and irrelevant features of a tool. Anim. Cogn., 6(4), 269–281.
Abstract: Few studies have examined whether non-human tool-users understand the properties that are relevant for a tool's function. We tested cotton-top tamarins (Saguinus oedipus) and rhesus macaques (Macaca mulatta) on an expectancy violation procedure designed to assess whether these species make distinctions between the functionally relevant and irrelevant features of a tool. Subjects watched an experimenter use a tool to push a grape down a ramp, and then were presented with different displays in which the features of the original tool (shape, color, orientation) were selectively varied. Results indicated that both species looked longer when a newly shaped stick acted on the grape than when a newly colored stick performed the same action, suggesting that both species perceive shape as a more salient transformation than color. In contrast, tamarins, but not rhesus, attended to changes in the tool's orientation. We propose that some non-human primates begin with a predisposition to attend to a tool's shape and, with sufficient experience, develop a more sophisticated understanding of the features that are functionally relevant to tools.
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Strickman, D. (1982). Notes on Tabanidae (Diptera) from Paraguay. J Med Entomol, 19(4), 399–402.
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Cowley, J. J., & Griesel, R. D. (1966). The effect on growth and behaviour of rehabilitating first and second generation low protein rats. Anim. Behav., 14(4), 506–517.
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De Stoppelaire, G. H., Gillespie, T. W., Brock, J. C., & Tobin, G. A. (2004). Use of remote sensing techniques to determine the effects of grazing on vegetation cover and dune elevation at Assateague Island National Seashore: impact of horses. Environ Manage, 34(5), 642–649.
Abstract: The effects of grazing by feral horses on vegetation and dune topography at Assateague Island National Seashore were investigated using color-infrared imagery, lidar surveys, and field measurements. Five pairs of fenced and unfenced plots (300 m2) established in 1993 on sand flats and small dunes with similar elevation, topography, and vegetation cover were used for this study. Color-infrared imagery from 1998 and field measurements from 2001 indicated that there was a significant difference in vegetation cover between the fenced and unfenced plot-pairs over the study period. Fenced plots contained a higher percentage of vegetation cover that was dominated by American beachgrass (Ammophila breviligulata). Lidar surveys from 1997, 1999, and 2000 showed that there were significant differences in elevation and topography between fenced and unfenced plot-pairs. Fenced plots were, on average, 0.63 m higher than unfenced plots, whereas unfenced plots had generally decreased in elevation after establishment in 1993. Results demonstrate that feral horse grazing has had a significant impact on dune formation and has contributed to the erosion of dunes at Assateague Island. The findings suggest that unless the size of the feral horse population is reduced, grazing will continue to foster unnaturally high rates of dune erosion into the future. In order to maintain the natural processes that historically occurred on barrier islands, much larger fenced exclosures would be required to prevent horse grazing.
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Dauphin, G., Zientara, S., Zeller, H., & Murgue, B. (2004). West Nile: worldwide current situation in animals and humans. Comp Immunol Microbiol Infect Dis, 27(5), 343–355.
Abstract: West Nile (WN) virus is a mosquito-borne flavivirus that is native to Africa, Europe, and Western Asia. It mainly circulates among birds, but can infect many species of mammals, as well as amphibians and reptiles. Epidemics can occur in rural as well as urban areas. Transmission of WN virus, sometimes involving significant mortality in humans and horses, has been documented at erratic intervals in many countries, but never in the New World until it appeared in New York City in 1999. During the next four summers it spread with incredible speed to large portions of 46 US states, and to Canada, Mexico, Central America and the Caribbean. In many respects, WN virus is an outstanding example of a zoonotic pathogen that has leaped geographical barriers and can cause severe disease in human and equine. In Europe, in the past two decades there have been a number of significant outbreaks in several countries. However, very little is known of the ecology and natural history of WN virus transmission in Europe and most WN outbreaks in humans and animals remain unpredictable and difficult to control.
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Malek, E. A. (1971). The life cycle of Gastrodiscus aegyptiacus (Cobbold, 1876) Looss, 1896 (Trematoda: Paramphistomatidae: Gastrodiscinae). J Parasitol, 57(5), 975–979.
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