Emeritus Professor of Biological Anthropology Barry Bogin provides an answer as part of The Conversation's Curious Kids series, which gives children the chance to have their questions about the world answered by experts.

Here's what he had to say... 

This is a brilliant question. Humans have evolved differently to other animals. We have much bigger brains relative to body size and in absolute size than other mammals, and have a level of intelligence that other animals don’t.

There are many advantages to intelligence, such as the ability to plan and cooperate, innovate new techniques and share information about what works.

The reason that living things evolve certain features, like stripes on a tiger, bright colours on a butterfly or a big brain in humans, is that these features have benefits that help them survive. The living things with these beneficial features then pass them on to their offspring.

There are a number of hypotheses – ideas – about the origins of human intelligence. The one I do my research work on is called biocultural reproduction.

Having big brains allows humans to keep more babies alive than other animals. According to the biocultural reproduction hypothesis, how intelligence helps us to keep babies alive comes down to how we care for each other – and especially how we look after children.

Helping each other

Many animals live in small or large social groups, and some social species of birds and mammals, such as meerkats, help each other to feed and protect their babies. This is called cooperative breeding. The helper animals don’t have any babies of their own. They give up their own reproduction to assist a dominant family member, such as their mother or older sister.

Parents and other carers may invest in young people for many years, sometimes for all their life. I am a parent and I continue to help my grown-up offspring, and their offspring – my grandchildren. This helping is what scientists call biocultural reproduction.

The carers may be genetically related to the child they look after, but they also may not be. The rules for how people care for each other are not set by genes, but by the names we give each other. These are not names like Sami or Barry, but things like “daughter”, “auntie”, “grandfather”, “cousin” or “friend”.