Spatial Clustering Of Chimpanzee Locations For Neighborhood Identification

Date of Submission: 
September 15, 2005
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Since 1960, the chimpanzees (Pan troglodytes) of Gombe National Park, Tanzania, have been studied by behavioral ecologists, including Jane Goodall. Data has been collected for the last 40 years and it is now being further analyzed by researchers in order to increase our understanding of the social structure of chimpanzees. In this paper, we consider the following question of interest to behavioral ecologists Does clustering exist among female chimpanzees in terms of the spatial locations visited by them? The analysis of this question will help behavioral ecologists to learn about the space use and the social interactions between female chimpanzees. The data collected for this analysis are marked spatial point patterns over the park. Current spatial clustering methods lack the ability to handle such marked point patterns directly. This paper presents a novel application of spatial point pattern analysis and data mining techniques to the ecological problem of clustering female chimpanzees. We studied various spatial analysis techniques and found that the Ripleys K-function provides a powerful tool for evaluating clustering behavior among spatial point patterns. We then proposed two clustering approaches for marked point patterns based on this widely-used statistical K-function. Experimental results using the proposed clustering methods provide significant insight into the dynamics of female chimpanzee space use and into the overall social stucture of the species. In addition, the methods proposed here can be extended to also include temporal information.