Although people are very skilled at using their hands, they take a long time to master how to use them. Meanwhile, for many apes, the process of mastery happens much faster- by the time humans have mastered their manual skills, many apes are already giving birth. Now, researchers from the University of Zurich have found out why.
For more than seven years, Sandra Heldstab, an evolutionary biologist, and her colleagues observed 36 different primate species. Overall, they studied 128 young primates in 13 zoos across Europe from birth until they reached full adult manual dexterity.
In particular, they found that all species tend to learn their respective manual skills in the same order. This, they said, highlights that the neural development of primates follows a very rigid pattern.
They also found that large-brained species like macaques, gorillas, and chimpanzees can solve more complex tasks with their hands than their smaller-brained cousins such as lemurs and marmosets. From this, they deduced that manual dexterity is likely a natural byproduct of having a larger brain.
More complex manual abilities, however, take a longer time to master. The researchers say this is because the range of these skills is more complex, and that more advanced skills are only encountered later on in life. They added that this might happen as human brains tend to be less developed at birth than those of apes with comparably smaller brains like lemurs and callitrichids.
“Our study shows once again that in the course of evolution, only mammals that live a long time and have enough time to learn were able to develop a large brain and complex fine motor skills including the ability to use tools. This makes it clear why so few species could follow our path and why humans could become the most technologically accomplished organism on this planet,” says Sandra Heldstab.