Human use energy in brains, muscles differently than chimps do

The way human brains and muscles use energy is strikingly distinct from chimpanzees’ metabolism in these tissues, a finding that may explain the major differences between the two species. An analysis of glucose and other metabolic compounds in brain and muscle tissue from humans, chimpanzees, macaque monkeys and mice shows that levels of metabolic compounds are similar in each tissue type across closely related species, with two exceptions — humans’ frontal cortex in the brain and human muscle tissue, researchers report May 27 in PLOS Biology. The team also found that based on weight, humans, including university basketball players, were weaker than chimpanzees and monkeys. The results suggest that early humans may have traded brute strength for endurance to fuel the growth of bigger brains.