|
|
Chappell, J., & Kacelnik, A. (2004). Selection of tool diameter by New Caledonian crows Corvus moneduloides. Anim. Cogn., 7(2), 121–127.
Abstract: One important element of complex and flexible tool use, particularly where tool manufacture is involved, is the ability to select or manufacture appropriate tools anticipating the needs of any given task-an ability that has been rarely tested in non-primates. We examine aspects of this ability in New Caledonian crows-a species known to be extraordinary tool users and manufacturers. In a 2002 study, Chappell and Kacelnik showed that these crows were able to select a tool of the appropriate length for a task among a set of different lengths, and in 2002, Weir, Chappell and Kacelnik showed that New Caledonian crows were able to shape unfamiliar materials to create a usable tool for a specific task. Here we examine their handling of tool diameter. In experiment 1, we show that when facing three loose sticks that were usable as tools, they preferred the thinnest one. When the three sticks were presented so that one was loose and the other two in a bundle, they only disassembled the bundle when their preferred tool was tied. In experiment 2, we show that they manufacture, and modify during use, a tool of a suitable diameter from a tree branch, according to the diameter of the hole through which the tool will have to be inserted. These results add to the developing picture of New Caledonian crows as sophisticated tool users and manufacturers, having an advanced level of folk physics.
|
|
|
|
Hunt, G. R., & Gray, R. D. (2004). Direct observations of pandanus-tool manufacture and use by a New Caledonian crow (Corvus moneduloides). Anim. Cogn., 7(2), 114–120.
Abstract: New Caledonian crows are reported to have impressive pandanus-tool manufacture abilities. These claims are based on an extensive artefact record. However, inferring behavioural and cognitive abilities without direct observation of tool manufacture is problematic. Here we report (and document on video) direct observations of a crow making and using stepped pandanus tools at Pic Ningua. We observed (1) a bias for making tools on left edges consistent with that previously found at the site, (2) faithful manufacture of a stepped design with high overall congruence in the shapes of tools, (3) the use of convergent rips to first form the tapered end working away from the trunk then the wide end working towards the trunk, (4) appropriate functional use of stepped tools by use of the leaf-edge barbs to hook food from holes, and (5) consistent holding of tools on the left side of its head when using them. Our observations verify most of the claims based on the artefact record, but the crow's exact manufacture technique was slightly different to that inferred previously.
|
|
|
|
Matsuzawa, T. (2003). The Ai project: historical and ecological contexts. Anim. Cogn., 6(4), 199–211.
Abstract: This paper aims to review a long-term research project exploring the chimpanzee mind within historical and ecological contexts. The Ai project began in 1978 and was directly inspired by preceding ape-language studies conducted in Western countries. However, in contrast with the latter, it has focused on the perceptual and cognitive capabilities of chimpanzees rather than communicative skills between humans and chimpanzees. In the original setting, a single chimpanzee faced a computer-controlled apparatus and performed various kinds of matching-to-sample discrimination tasks. Questions regarding the chimpanzee mind can be traced back to Wolfgang Koehler's work in the early part of the 20th century. Yet, Japan has its unique natural and cultural background: it is home to an indigenous primate species, the Japanese snow monkey. This fact has contributed to the emergence of two previous projects in the wild led by the late Kinji Imanishi and his students. First, the Koshima monkey project began in 1948 and became famous for its discovery of the cultural propagation of sweet-potato washing behavior. Second, pioneering work in Africa, starting in 1958, aimed to study great apes in their natural habitat. Thanks to the influence of these intellectual ancestors, the present author also undertook the field study of chimpanzees in the wild, focusing on tool manufacture and use. This work has demonstrated the importance of social and ecological perspectives even for the study of the mind. Combining experimental approaches with a field setting, the Ai project continues to explore cognition and behavior in chimpanzees, while its focus has shifted from the study of a single subject toward that of the community as a whole.
|
|
|
|
Yamazaki, Y., Shinohara, N., & Watanabe, S. (2004). Visual discrimination of normal and drug induced behavior in quails (Coturnix coturnix japonica). Anim. Cogn., 7(2), 128–132.
Abstract: The ability to discriminate the physical states of others could be an adaptive behavior, especially for social animals. For example, the ability to discriminate illness behavior would be helpful for avoiding spoiled foods. We report on an experiment with Japanese quails testing whether these birds can discriminate the physical states of conspecifics. The quails were trained to discriminate between moving video images of quails injected with psychoactive drugs and those in a normal (not injected) condition. Methamphetamine (stimulant) or ketamine (anesthetic) were used to produce drug-induced behaviors in conspecifics. The former induced hyperactive behavior and the latter hypoactive behavior. The subject quails could learn the discrimination and showed generalization to novel images of the drug-induced behaviors. They did not, however, show discriminative behavior according to the type and dosage of the drugs. Thus, they categorized the behavior not on the basis of degree of activity, but on the basis of abnormality.
|
|
|
|
Goto, K., Wills, A. J., & Lea, S. E. G. (2004). Global-feature classification can be acquired more rapidly than local-feature classification in both humans and pigeons. Anim. Cogn., 7(2), 109–113.
Abstract: When humans process visual stimuli, global information often takes precedence over local information. In contrast, some recent studies have pointed to a local precedence effect in both pigeons and nonhuman primates. In the experiment reported here, we compared the speed of acquisition of two different categorizations of the same four geometric figures. One categorization was on the basis of a local feature, the other on the basis of a readily apparent global feature. For both humans and pigeons, the global-feature categorization was acquired more rapidly. This result reinforces the conclusion that local information does not always take precedence over global information in nonhuman animals.
|
|
|
|
Neff, B. D., & Sherman, P. W. (2003). Nestling recognition via direct cues by parental male bluegill sunfish ( Lepomis macrochirus). Anim. Cogn., 6(2), 87–92.
Abstract: Parental care can be costly to a parent in terms of both time and energy invested in the young. In species with cuckoldry or brood parasitism not all of the young under a parent's care are necessarily offspring. In such cases, distinguishing between kin and non-kin, and investing only in the former (nepotism), can be advantageous. Bluegill sunfish ( Lepomis macrochirus) are characterized by paternal care and cuckoldry, and care-providing males appear to show nepotistic behaviours. Here, we investigated nestling recognition in bluegill, determining whether parental males can differentiate between young from their own nest (familiar and related) and young from non-neighbouring nests (unfamiliar and unrelated) using (1) visual and chemical cues, and (2) chemical cues only. In the first experiment, wild-caught parental males were presented with samples of eggs or fry (newly hatched eggs) collected from their own nest or a foreign nest and placed on opposite sides of an aquarium. The time these parental males spent associating with each sample, and their “pecking” behaviours (indicating cannibalism), were recorded. Parental males showed no preference between eggs from their own nest and eggs from a non-neighbouring nest, but they preferred to associate with fry from their own nest over foreign fry. There also was a positive relationship between male body size and the time spent associated with fry from their own nest. Parental males pecked at foreign fry more than 5 times as often as fry from their own nest, though this difference was not statistically significant. In the second experiment, fry that were collected from the nest of a wild-caught parental male or a non-neighbouring nest were placed in different containers and the water from each was dripped into opposite ends of an aquarium. The time the male spent on each side was recorded. In this case, parental males spent more time near the source of water conditioned by unrelated fry, but there was a positive relationship between male condition (fat reserves) and the time he spent near the source of water conditioned by fry from his own nest. Results confirm that chemicals cue nestling recognition by parental male bluegill.
|
|
|
|
Sundaresan, S. R., Fischhoff, I. R., Dushoff, J., & Rubenstein, D. I. (2007). Network metrics reveal differences in social organization between two fission-fusion species, Grevy's zebra and onager. Oecologia, 151(1), 140–149.
Abstract: For species in which group membership frequently changes, it has been a challenge to characterize variation in individual interactions and social structure. Quantifying this variation is necessary to test hypotheses about ecological determinants of social patterns and to make predictions about how group dynamics affect the development of cooperative relationships and transmission processes. Network models have recently become popular for analyzing individual contacts within a population context. We use network metrics to compare populations of Grevy's zebra (Equus grevyi) and onagers (Equus hemionus khur). These closely related equids, previously described as having the same social system, inhabit environments differing in the distribution of food, water, and predators. Grevy's zebra and onagers are one example of many sets of coarsely similar fission-fusion species and populations, observed elsewhere in other ungulates, primates, and cetaceans. Our analysis of the population association networks reveals contrasts consistent with their distinctive environments. Grevy's zebra individuals are more selective in their association choices. Grevy's zebra form stable cliques, while onager associations are more fluid. We find evidence that females associate assortatively by reproductive state in Grevy's zebra but not in onagers. The current approach demonstrates the utility of network metrics for identifying fine-grained variation among individuals and populations in association patterns. From our analysis, we can make testable predictions about behavioral mechanisms underlying social structure and its effects on transmission processes.
|
|
|
|
Owren, M. J., Dieter, J. A., Seyfarth, R. M., & Cheney, D. L. (1993). Vocalizations of rhesus (Macaca mulatta) and Japanese (M. fuscata) macaques cross-fostered between species show evidence of only limited modification. Dev Psychobiol, 26(7), 389–406.
Abstract: Two rhesus and two Japanese macaque infants were cross-fostered between species in order to study the effects of auditory experience on vocal development. Both the cross-fostered and normally raised control subjects were observed over the first 2 years of life and their vocalizations were tape-recorded. We classified 8053 calls by ear, placed each call in one of six acoustic categories, and calculated the rates at which different call-types were used in different social contexts. Species differences were found in the use of “coo” and “gruff” vocalizations among control subjects. Japanese macaques invariably produced coos almost exclusively. In contrast, rhesus macaques produced a mixture of coos and gruffs and showed considerable interindividual variation in the relative use of one call type or the other. Cross-fostered Japanese macaques adhered to their species-typical behavior, rarely using gruffs. Cross-fostered rhesus subjects also exhibited species-typical behavior in many contexts, but in some situations produced coos and gruffs at rates that were intermediate between those shown by normally raised animals of the two species. This outcome suggests that environmentally mediated modification of vocal behavior may have occurred, but that the resulting changes were quite limited.
|
|
|
|
Henry, S., Richard-Yris, M. - A., & Hausberger, M. (2006). Influence of various early human-foal interferences on subsequent human-foal relationship. Dev Psychobiol, 48(8), 712–718.
Abstract: Whereas the way animals perceive human contact has been particularly examined in pet animals, a small amount of investigations has been done in domestic ungulates. It was nevertheless assumed that, as pet animals, non-aggressive forms of tactile contact were as well rewarding or positive for these species, even though the features of intraspecific relationships in pet animals and domestic ungulates may be to some extent different.We test here the hypothesis that horses may not consider physical handling by humans as a positive event. When comparing different early human-foal interactions, we found that early exposure to a motionless human enhanced slightly foals reactions to humans whereas forced stroking or handling in early life did not improve later human-foal relation. Foals that were assisted during their first suckling (e.g., brought to the dam's teat) even tended to avoid human approach at 2 weeks, and physical contact at 1 month of age.We argue that interspecies differences may exist in how tactile stimulation is perceived. It may be important for the establishment of a bond that a young animal is active in the process and able, through its behavioral responses, to help define what is positive for it. This way of investigation may have important general implications in how we consider the development of social relations, both within and between species.
|
|
|
|
Koski, S. E., Koops, K., & Sterck, E. H. M. (2007). Reconciliation, relationship quality, and postconflict anxiety: testing the integrated hypothesis in captive chimpanzees. Am. J. Primatol., 69(2), 158–172.
Abstract: Reconciliation is a conflict resolution mechanism that is common to many gregarious species with individualized societies. Reconciliation repairs the damaged relationship between the opponents and decreases postconflict (PC) anxiety. The “integrated hypothesis” links the quality of the opponents' relationship to PC anxiety, since it proposes that conflicts among partners with high relationship quality will yield high levels of PC anxiety, which in turn will lead to an increased likelihood of reconciliation. We tested the integrated hypothesis in captive chimpanzees (Pan troglodytes) in the Arnhem Zoo, The Netherlands. We applied the standard PC/matched control (MC) method. Our results mostly support the integrated hypothesis, in that more valuable and compatible partners (i.e., males and frequent groomers) reconciled more often than less valuable and weakly compatible partners (i.e., females and infrequent groomers). In addition, PC anxiety was higher after conflicts among males than among females. Emotional arousal thus appears to be a mediator facilitating reconciliation. However, in contrast to the predictions derived from the integrated hypothesis, PC anxiety appeared only in aggressees, and not in aggressors, of conflicts. This suggests that while relationship quality determines PC anxiety, it is dependent on the role of the participants in the conflict.
|
|
