Research suggests that gut microbes may influence behavior in mice, with some studies indicating they can make mice lazy, while others found that certain gut microbes can increase exercise in mice. The relationship between gut microbes and behavior is being explored, with some studies involving fecal transplants that appear to have a rejuvenating effect on the brains of older mice. The implications of these findings for humans are still being considered, with questions about whether gut microbes can affect human behavior and athletic performance.