STATES CHRONICLE – A new study reveals that primates might have grown larger brains due to fruit diets, developing more complex brains. Scientists compared the diets and brain sizes of more than 140 species of primates, like lorises, lemurs, monkeys and apes. They uncovered that those primates which were used to have fruit diets instead of consuming only leaves had 25% more brain tissue compared to those which did not consume fruits.
Primates which had fruit diets proved to have bigger and more complex brains
For instance, howler monkeys and spider monkeys both live in South America, in the jungles of the rain forest, in groups of 10 members. However, howler monkeys eat trumpet tree leaves every day, while spider monkeys consume passion fruit and other fruits. Despite the fact that both species of monkeys live in similar environments and they have a similar social setting, howler monkeys have a smaller brain than spider monkeys.
Alex DeCasien, a doctoral candidate at New York University and also the lead author of the study, argued that if there are some species which feed on fruits instead of leaves, this means that they have all the cognitive methods developed to deal with this idea. Fruit usually vary from one season to another, and some of them might be hard to reach to. That is why those primates which consume fruits need a lot of strength and skills to reach to feed on fruits.
Diets based on animal proteins or fruits helped primates develop their cognitive skills
Primates which have bigger brains could be apt to fulfill their goal, grab the fruits and eat them. All this process is a lot more complicated than just extending your arm to catch a leaf and eat it. Thus, specialists argue that a fruit diet may have led to the evolution of primates’ brains over generations. Apes and monkeys which have diets based on animal proteins also revealed to have bigger brains compared to the ones which only fed on leaves.
Researchers claim that primates who had a protein diet needed more cognitive skills to hunt, being able to feed on insects, birds, and frogs, compared to the ones which had a lower cognitive power since all they did every day was to eat leaves. Nevertheless, DeCasien stated that she and her team of researchers were surprised to uncover that leaf eaters had smaller brains than fruit eaters.
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