Prey or play: interactions between walruses and seabirds
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- 作者：Andrey Giljov ; Karina Karenina ; Anatoly Kochnev
- 关键词：Walrus behaviour ; Seabirds ; Predatory behaviour ; Play ; Social behaviour ; Visual lateralisation
- 刊名：acta ethologica
- 出版年：2017
- 出版时间：February 2017
- 年：2017
- 卷：20
- 期：1
- 页码：47-57
- 全文大小：
- 刊物类别：Biomedical and Life Sciences
- 刊物主题：Behavioral Sciences; Zoology; Evolutionary Biology;
- 出版者：Springer Berlin Heidelberg
- ISSN：1437-9546
- 卷排序：20
文摘
Several anecdotal reports indicate that walruses (Odobenus rosmarus) occasionally attack seabirds, which potentially impacts local bird populations. However, the manner in which walruses interact with seabirds and the motivational basis of such interactions have not been investigated. Here, we describe and characterize the behaviour of wild Pacific walruses (O. r. divergens) directed at seabirds in water near the summer haulout in the Chukchi Sea. Although most walruses showed no interest in seabirds nearby, some individuals intentionally approached them both alone and in groups. A total of 74 seabird encounters for 71 individually identified walruses were registered. Behavioural analysis based on detailed observations, photography and video recording showed that the most common types of walrus behaviour toward a bird were approach by surfacing and splash, approach by surfacing and hit and attack from below. Immature individuals initiated 82% of encounters. The motivation to approach a bird was low in adult individuals, with the majority of encounters involving adults initiated by males. Walrus encounters with live birds showed a very low rate of bird kill. Encounters with dead birds were followed by further manipulations with bird carcasses, which included both the consumption of bird soft tissue and object play taking the form of drop–catch behaviour. In addition eight cases of the object-oriented play with a bird carcass in a group of walruses were observed. Object play in wild walruses is reported for the first time. Our results indicate that in seabird encounters, walruses display diverse behavioural patterns, not limited to predatory responses.