Aggression and group size in domesticated pigs, Sus scrofa:: 'when the winner takes it all and the loser is standing small'
Aggression and group size in domesticated pigs, Sus scrofa:: 'when the winner takes it all and the loser is standing small'
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DOI：
10.1016/j.anbehav.2003.12.016
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发表时间：
2004-10-01
期刊：
影响因子：
2.5
通讯作者：
Boe, KE
中科院分区：
文献类型：
--
作者：
Andersen, IL;Nævdal, E;Boe, KE
在今天的畜牧业系统中，家养物种的人工群体的形成经常发生。这些群体被关在一个封闭的空间里，个人无法退出群体，环境中的资源通常是有限的和可防御的。这创造了一个充满竞争的环境，在这里经常可以看到攻击性和社会压力。我们开发了一个理论模型，描述了不熟悉的猪之间的攻击是如何作为群体规模的函数的。随着潜在竞争者数量的增加，更多的个体将从不卷入代价高昂的争斗中受益。其原因是，能够垄断资源的可能性随着群体规模的增加而减少。为了验证该模型的预测，我们比较了三组（6头、12头和24头）不熟悉的断奶仔猪的攻击行为。6头猪和12头猪组成的猪群的打斗次数明显多于24头猪组成的猪群，而且最大的猪群中不参与打斗的猪的比例也明显更高。对于那些愿意在最大群体中冒险打架的猪来说，每次打架的持续时间比在较小群体中打架的持续时间长。这些结果支持了我们理论模型的预测，我们得出结论，猪能够根据实际竞争情况随着群体规模的变化而改变自己的行为。(C) 2004动物行为研究协会。Elsevier Ltd.出版。版权所有。
Formation of artificial groups of domestic species occurs frequently in today's husbandry systems. These groups are kept in a closed space where the individuals are not able to withdraw from the group, and resources in the environment are most commonly limited and defensible. This creates a competitive environment where aggression and social stress are often seen. We developed a theoretical model that describes how aggression among unacquainted pigs is a function of group size. As the number of potential competitors increases, more individuals will benefit from not getting involved in costly fights. The reason for this is that the probability of being able to monopolize resources diminishes as group size increases. To verify predictions from this model, we compared aggression among unacquainted, weaned pigs in three group sizes (6, 12 and 24 pigs). There were significantly more fights per individual in groups of six and 12 pigs than in groups of 24 pigs, and the proportion of pigs not participating in fights was significantly higher in the largest group. For pigs that were willing to take the risk of getting involved in fights in the largest group size, the duration of each fight was longer than for fights in the smaller groups. These results support the predictions from our theoretical model, and we conclude that pigs are able to alter their behaviour according to how the actual competitive situation changes with group size. (C) 2004 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.