New research has shown that human teeth have decreased in size as our brains have become larger over the last 2.5 million years. Researchers in Spain have described the finding as an ‘evolutionary paradox and suggested that the changes could have come about due to drastic alterations in diet. The study involved a variety of primates and revealed that humans are the only ones who have smaller teeth in relation to brain size.
Previous ideas about human evolution would suggest that mankind needed to eat more to support a growing brain and higher metabolism, which would in turn lead to larger teeth; however, experts believe that as humans started to eat more nutritious foods, like animal meat, this enabled the same amount of proteins and fats to be absorbed without the need for a greater quantity.
Lead researcher Juan Manuel Jimenez-Arenas, wrote in the research article that ‘Brain volume and cheek-tooth size had traditionally been considered as two traits that show opposite evolutionary trends during the evolution of Homo. Here we show that there is an essential difference between the genus Homo and the living primate species.’ It was also revealed that humans are the only primates to show an ‘inverse relationship’ with teeth and brain size, compared to other primates. The shrinking of the teeth could possibly be a genetic change, based on the inactivation of a gene called MYH16 – which is linked to brain structure.