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Current Herpetology
Abstract
Abstract:
Most lizards have well developed auditory abilities, while not actually vocalizing to any extent outside of geckos. However, except for geckos, function of hearing in lizards has not been well investigated. Recently, the ability to eavesdrop on the alarm calls of a syntopic avian species has been demonstrated in four species of lizards that belong to different families. This suggests that eavesdropping is a major function of hearing in lizards. To examine this possibility we tested the ability of heterospecific eavesdropping by a lizard that belongs to another family in an Ampijoroa forest of Madagascar, where two lizard species have been known to show this ability. We experimentally tested whether Zonosaurus laticaudatus, a gerrhosaurid lizard, has the ability to eavesdrop on the alarm calls of the Madagascar paradise flycatcher. In the experiment, we provided bait on the ground in front of free-ranging zonosaurs to induce their foraging activity and played back alarm calls or songs of the bird to them. The number of individuals that stopped foraging in response to the alarm calls was larger than that in response to the songs. Similarly, the number of individuals that fled in response to the alarm calls was larger than that in response to the songs. The zonosaurs stopped foraging for a longer time in response to the alarm calls than to the songs. These results demonstrate that Z. laticaudatus has the ability to eavesdrop on alarm calls of the Madagascar paradise flycatcher. It is suggested that heterospecific eavesdropping by non-vocal lizards is a common phenomenon, at least, in the Ampijoroa forest of Madagascar.
We are grateful to M. Nakamura, M. Hasegawa, I. Ikeuchi, H. Takahashi, H. Sato, B. Razafimahatratra, T. M. Randriamboavonjy, and zoological researchers working in the Ampijoroa forest for their assistance in the field, to T. Mizuta for his technical help in recording and editing bird songs and calls, and to F. Rakotondraparany and H. Rakotomanana for their help in arranging and conducting this research. We also thank the staff of Madagascar National Parks for their cooperation in conducting this research. This research was financially supported in part by JSPS Grants-in-Aid for Scientific Research (B: nos. 21405007 and 24405008) and for Young Scientists (B: no. 25870369) and in part by 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 (authorisation no. 246/08).
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