CREAF (Centre for Ecological Research and Applied Forestries), Autonomous University of Barcelona, Bellaterra, Catalonia, Spain.
J Evol Biol. 2010 May;23(5):1064-74. doi: 10.1111/j.1420-9101.2010.01976.x. Epub 2010 Mar 24.
Many mammals have brains substantially larger than expected for their body size, but the reasons for this remain ambiguous. Enlarged brains are metabolically expensive and require elongated developmental periods, and so natural selection should have favoured their evolution only if they provide counterbalancing advantages. One possible advantage is facilitating the construction of behavioural responses to unusual, novel or complex socio-ecological challenges. This buffer effect should increase survival rates and favour a longer reproductive life, thereby compensating for the costs of delayed reproduction. Here, using a global database of 493 species, we provide evidence showing that mammals with enlarged brains (relative to their body size) live longer and have a longer reproductive lifespan. Our analysis supports and extends previous findings, accounting for the possible confounding effects of other life history traits, ecological and dietary factors, and phylogenetic autocorrelation. Thus, these findings provide support for the hypothesis that mammals counterbalance the costs of affording large brains with a longer reproductive life.
许多哺乳动物的大脑相对于其体型而言明显较大，但这一现象的原因仍不清楚。大脑的增大在新陈代谢方面是昂贵的，并且需要延长发育周期，因此，如果大脑的增大没有带来相应的优势，自然选择应该会有利于其进化。一个可能的优势是促进对异常、新颖或复杂的社会生态挑战的行为反应的构建。这种缓冲效应应该会提高存活率，并有利于更长的生殖寿命，从而弥补繁殖延迟的成本。在这里，我们利用一个包含 493 个物种的全球数据库，提供了证据表明，大脑相对于体型较大的哺乳动物寿命更长，生殖寿命更长。我们的分析支持并扩展了以前的发现，考虑了其他生活史特征、生态和饮食因素以及系统发育自相关的可能混杂影响。因此，这些发现为以下假设提供了支持，即哺乳动物通过延长生殖寿命来平衡大脑增大的成本。
