Abstract
Recent rapid urbanization has imposed novel challenges to animals. Urban animals alter their behaviors such as increased boldness, exploration, and aggressiveness to cope with anthropogenic disturbance. However, most previous studies were highly biased toward birds and examined a limited number of behavioral traits, often employing species-specific methods. Thus, we still do not fully understand how other taxa behaviorally adjust to urbanization. In this study, we investigated multiple behavioral traits between urban and rural Eurasian red squirrels, Sciurus vulgaris, which is one of the typical urban colonizers across northern Eurasia. The open field test (OFT) and mirror image stimulation (MIS), two well-established methods for quantifying animal personality, were employed for behavioral comparisons. We also used several other measurements, such as flight distances and the number of mobbing calls directed at humans. The principal component analysis approach for OFT and MIS provided an activity-shyness axis and stress response axis in OFT and sociability-avoidance axis in MIS, which had significant repeatability within individuals. However, most axes were not significantly different between urban and rural areas, while the stress response of urban squirrels was significantly weaker than that of rural conspecifics. On the contrary, human-related behaviors such as flight distance and the number of mobbing calls toward humans were significantly different between urban and rural habitats. Therefore, behavioral modifications reported in previous studies might reflect only human-related disturbances: some urban animals such as mammals may be able to flexibly change behaviors depending on the situation, while their innate character or personality remains unchanged. This study underscores the importance of measuring multiple behaviors using different methods in non-avian species, focusing especially on human-associated behaviors.
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Acknowledgments
We are thankful for the valuable comments helping us to establish experimental procedures from Dr. M. J. Merrick. We also appreciate Dr. D.T. Blumstein for advising us on data analysis of behaviors. C. Ayer and J. L. Anders kindly corrected the English. We also acknowledge M. Watanabe, I. Tanio, R. Okawa, Y. Takahata, and Wildlife Management, Obihiro University of Agriculture and Veterinary Medicine for helping with the field survey, and the Laboratory of Animal Ecology, Hokkaido University for numerous discussions. This work was supported by Grant-in-Aid for JSPS Research Fellow Grant Number JP17J04255. All procedures involving capturing and handling of squirrels were ethically approved by the Institutional Animal Care and Use Committee of National University Corporation Hokkaido University (license number 15-0121).
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Uchida, K., Shimamoto, T., Yanagawa, H. et al. Comparison of multiple behavioral traits between urban and rural squirrels. Urban Ecosyst 23, 745–754 (2020). https://doi.org/10.1007/s11252-020-00950-2
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DOI: https://doi.org/10.1007/s11252-020-00950-2