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"... r 1 as rel d e c experiments, subjects were required to pull a piece of cloth to gain access to a piece of food. The first experiment involved choosing between food that was on the cloth and food that was off the cloth. The second experiment involved choosing between food that was on a connected pie ..."
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r 1 as rel d e c experiments, subjects were required to pull a piece of cloth to gain access to a piece of food. The first experiment involved choosing between food that was on the cloth and food that was off the cloth. The second experiment involved choosing between food that was on a connected piece of cloth and food that was on two pieces of cloth separated by a horizontal gap. Having learned to solve either of these two problems, we conducted a series of probe conditions to determine whether the tamarins would generalize to changes in the shape, size, colour, and texture of the cloth and food, the position of the food relative to the cloth, and the type of connection between two pieces of cloth. For most of the probe conditions, the tamarins readily generalized, showing no decrement in performance, even on the first trial. For other conditions, involving apparently more subtle discrimination (e.g. a narrow vertical gap between the two pieces of cloth), explicit training was required. These results indicate that tamarins solve means–end relationships, and that their ability depends on a discrimination between properties that are functionally relevant as opposed to irrelevant. Ó 1999 The Association for the Study of Animal Behaviour Problem solving often involves an analysis of means–end relationships. In Kohler’s (1925) classic experiments on chimpanzees, for example, an individual was required to place a series of boxes under a hanging banana, stand on the boxes, and then use a stick to draw the banana closer. In this situation, as in any means–end analysis, some features of the problem are relevant to the task at hand, whereas other features are irrelevant. In Kohler’s task, the functionally relevant features concern the shapes and sizes of the boxes and sticks. In contrast, the colour of the boxes and sticks are irrelevant. But to what extent are animals sensitive to the distinction between functionally relevant and irrelevant features of a means–end task? This paper addresses this question by testing cotton-top tama-rins, Saguinus oedipus oedipus, on a series of means–end problems. Much of the recent work in this area has focused on the causal nature of tool use, and to some extent, the func-Visalberghi and colleagues (Visalberghi & Fragaszy 1991;
"... Compared to other species of tamarins and marmosets, callimicos (Callimico goeldii) are characterized by hindlimb and hindfoot elongation, and a pattern of locomotion dominated by leaping to and from vertical supports in the forest understory. We present field data on trunk-to-trunk leaping in a hab ..."
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Compared to other species of tamarins and marmosets, callimicos (Callimico goeldii) are characterized by hindlimb and hindfoot elongation, and a pattern of locomotion dominated by leaping to and from vertical supports in the forest understory. We present field data on trunk-to-trunk leaping in a habituated group of callimicos in northern Bolivia. We measured the DBH of the takeoff and landing platform, and the distance traveled during 110 trunk-to-trunk leaps. Our results indicate that mean distance leapt by callimicos was 1.8 m (range 0.2–4.3m). There were no significant differences in the size of takeoff (mean = 10.3 cm) and landing platforms (mean = 9.9 cm). In addition, longer leaps did not occur on larger diameter supports than did shorter leaps. Although tree trunks and saplings were the most commonly used takeoff and landing platforms, 31.8 % of the time callimicos jumped to and from bamboo culms. These data highlight the facts that trunk-to-trunk leaping represents a highly specialized pattern of locomotion in callimicos, and that these primates travel through mixed forests that include stands of bamboo and canopy trees. Conservation efforts to sustain viable populations of Callimico goeldii must focus on protecting and preserving habitats that contain large tracts of mixed bamboo and secondary forest. Key Words: callitrichines; locomotion; bamboo; habitat. Resumen Comparado con otras especies de tamarinos y monos titís, los callimicos (Callimico goeldii) se caracterizan por el alargamiento