Did climate change over the last few million years have an impact on the evolution of the human body? This is what researchers from the University of Cambridge and the University of Tübingen (Germany) suggest in a new study published on 8 July in the journal Nature Communications.
According to their findings, they even believe that climate, in particular temperature, has been 'one of the main drivers of changes in body size over the last million years,' as Andrea Manica, lead author of the study, explains to CNN.
Climate linked to body size
To reach this conclusion, the researchers studied the body and brain size of more than 300 fossils of the genus 'Homo,' to which we belong as Homo sapiens. They then associated the measurements with the different regional climates that these individuals would have experienced. And their findings are convincing: the size of the human body did indeed vary according to temperature.
Cold, hostile climates were associated with a larger body size, while warm climates were associated with a smaller body mass. Andrea Manica says:
Larger bodies can protect people from cold temperatures—the larger you are, the smaller your surface area relative to your volume, so you retain heat more effectively.
The brain raises questions
However, some grey areas remain, particularly concerning the size of the brain. The researcher goes on to say:
It is important to note, however, that climate explains much less of the changes in brain size than in body size.
This means that other factors such as the additional cognitive challenges associated with increasingly complex social lives, more diverse diets and more sophisticated technology were probably the main drivers of changes in brain size.