Ethogram of selected behaviors initiated by free-ranging short-finned pilot whales (Globicephala macrorhynchus) and directed to human swimmers during open water encounters

In order to establish an ethogram of interactive behaviors initiated by free-ranging short-finned pilot whales (Globicephala macrorhynchus) and directed to human swimmers, we initiated encounters with non-habituated pilot whale groups during open water encounters southwest of Tenerife, Canary Islands, over two field seasons (1996 and 2001). Human swimmers followed a precautionary set of rules during approaches. Encounters ranged in duration from 3 to 44 min (M = 14.1 min +/- SD = 7.6; n = 35). We describe 11 interactive behaviors and compare them with previously described interactive behaviors reported in the scientific literature on the same and other toothed whale species. In contrast to other researchers focusing on reports of aggressive behaviors initiated by free-ranging as well as captive short-finned pilot whales, we observed with one exception ("headshake") apparently affiliative and non-aggressive behaviors during this study. Several interactive behaviors were found to match descriptions from other researchers observing the same as well as other toothed whale species. During this study, swimmers behaved carefully and the number of swimmers was low. We strongly recommend to follow the code of conduct based upon the methodology described in the paper, e.g., low numbers of swimmers and no contact initiations by swimmers during human-pilot whale interactions, in order to reduce the likelihood of potentially dangerous aggressive interactions. (c) 2004 International Society for Anthrozoology