The Madagascan spiny-tailed iguana alters the sequence of anti-predator responses depending on predator types

Abstract

Some prey are able to avoid specific predators by altering defensive behaviours depending on predator type. In the Ampijoroa forest of Ankarafantsika National Park in Madagascar, Madagascan spiny-tailed iguanas (Oplurus cuvieri cuvieri) inhabit a species rich vertebrate community and are exposed to multiple potential predators, such as raptors and snakes. We examined the response of wild iguanas to visual stimuli of avian and serpent predators by presenting iguanas with either a hawk or snake model. In most cases, the iguanas fled following contact with the hawk model. Exposure to the snake model also mostly resulted in the iguanas fleeing, but this response was preceded by other behaviours (e.g. push-up and dewlapping) that were not exhibited in response to the hawk model. Our results suggest that the spiny-tailed iguana adaptively alters anti-predator responses depending on the hunting methods and risk level of the immediate predators.

Keywords:

• Oplurus cuvieri cuvieri
• predator-specific anti-predator behaviours
• predator type
• raptorial predator
• serpent predator
• risk level

Acknowledgements

We thank H. Numata, M. Imafuku, M. Hasegawa and T. Mizuta for their comments on earlier versions of this manuscript. We are grateful to T. Mizuta, I. Ikeuchi, H. Takahashi, H. Sato, B. Razafimahatratra, T. M. Randriamboavonjy, T. Randrianarisoa, F. D. Hanitrininosy and zoological researchers working in the Ampijoroa forest for their assistance in the field, to H. Sato for his support in the field, to B. Maradona for his assistance in experiments and to F. Rakotondraparany and H. Rakotomanana for their help in arranging and conducting this research. We would like to express our gratitude to S. Barribeau for helping us to improve the English in this paper. We also thank the staff of Madagascar National Parks for their cooperation in conducting this research. Experimental procedures adhered to the guidelines of Madagascar National Parks. This research was financially supported by Grants-in-Aid for the International Scientific Research Program (nos. 17405008 and 21405007) from the Ministry of Education, Culture, Sports, Science and Technology, Japan, and in part by a Grant for the Global COE Program (A06) to Kyoto University. The field study was conducted with permission from the Ministry of the Environment and Forests, Madagascar, through Madagascar National Parks.