Researchers implanted microbes from humans squirrel monkeys (large-brained species) and macaques (small-brained species) into mice observing that microbes from larger-brained primates enhanced energy production while those from smaller-brained primates favored fat storage.

The findings reveal that gut microbiota differences may have evolved to meet the higher energy demands of larger brains. This research offers a fresh perspective on human evolution emphasizing the potential of gut microbes to shape metabolic and biological traits.

Their findings showed the mice with microbes from large-brain primate species produced and used more energy while those with microbes from the small-brain species stored more energy as fat.

The data is the first to show gut microbes from different animal species shape variations in biology between animal species and supports the hypothesis that gut microbes might influence evolution by changing how an animals body works.

We know the community of microbes living in the large intestine can produce compounds that affect aspects of human biology for example causing changes to metabolism that can lead to insulin resistance and weight gain said the studys first author Katherine Amato associate professor of anthropology at Northwestern

They would also like to collect more information on the types of compounds the microbes are producing and gather additional data on the biological traits of the hosts such as immune function and behavior.

Source: https://neurosciencenews.com/microbiome-brain-size-evolution-28166/