An ancient barrage of exploding stars close to Earth is the main reason early humans learnt to walk on two feet rather than all fours, according to new research.
Scientists believe the intense period of supernovae, which peaked approximately 2.6 million years ago, caused a surge in lightning strikes which incinerated much of the heavily forested Earth.
Early humans then had to adapt from living in and around trees to surviving in open savannas, meaning the ability to cross exposed grassland at speed and spot predators above the vegetation became crucial.
Such general change in the environment won’t explain why just the one species became bipedal. Not really…..