An international team led by researchers from CREAF and the CSIC has analyzed 493 species of mammals to confirm that animals with larger brains live longer . The new study confirms the adaptive benefits of having a large brain.
? Traditionally it has been considered that one of the selective advantages of having a large brain is to facilitate the development of new behaviors to respond to ecological challenges that the individual has not experienced before, such as a sudden reduction in food or the emergence of a new predator ?, explains César González-Lagos, lead author of the study and researcher at the Center for Ecological Research and Forestry Applications (CREAF), associated with the Autonomous University of Barcelona.
The results, published in the Journal of Evolutionary Biology , reveal that species that have developed large brains live longer than those with small brains, as suggested by the protective brain hypothesis . According to this hypothesis, the brain would adopt a “protective” role that would reduce mortality and extend the reproductive life of individuals , thus offsetting the energy and development costs associated with a large brain. However, the evidence provided by the study is “correlative”, meaning that it does not “necessarily” indicate cause-effect.
What selective advantage does a big brain offer?
Throughout their evolutionary history, some mammals, such as primates, cetaceans, and elephants , have developed much larger brains than would be expected for their body size. But a big brain involves energy costs and development time. In The Descendant of Man (1871), the British naturalist Charles Darwin, always attracted by this question, thought that a large brain, like that of humans, improved the mental capacity of individuals, because natural selection favors the appearance of the big brains. Darwin believed that with a large brain, mental capacity improved. But what selective advantage can it offer? The controversy over the benefits of having a bigger brain continues.
