How brain and body size evolved in mammals over the last 150 million years
Brain size in mammals shows variation and similarities despite intelligence levels.
Scientists at Stony Brook University and the Max Planck Institute of Animal Behavior have pieced together a timeline of how brain and body size evolved in mammals over the last 150 million years. The findings, published in Science Advances, show that brain size relative to body size — long considered an indicator of animal intelligence –has not followed a stable scale over evolutionary time.
The team of scientists, including biologists, evolutionary statisticians and anthropologists, compared the brain mass of 1,400 living and extinct mammals. For the 107 fossils examined — among them ancient whales and the most ancient Old World monkey skull ever found — they used endocranial volume data from skulls instead of brain mass data. The brain measurements were then analyzed along with body size to compare the scale of brain size to body size over deep evolutionary time.