An ant's brain takes a quarter of its energy — and refuses to power down, just like ours

A human brain is about 2% of body weight but burns roughly 20% of our energy. Boston University researchers have now found almost the same maths in a pavement ant: its brain is about 5% of its body weight and uses about a quarter of its energy. Publishing in the Proceedings of the National Academy of Sciences, Zachary Coto and James Traniello's team went further: when worker ants were starved, their bodies sharply cut energy use while their brains kept running at nearly full capacity — and the ants could still recognise nestmates and defend the colony. Shrinking a mammal brain to ant size in their models predicted the same energy bill, suggesting that protecting the brain first, at almost any scale, is a deep rule of evolution rather than a human special case. 'Even miniature brains are expensive to run,' the team notes, 'and even in social insects that put the colony above the individual, prioritising energy for brain processing remains essential.'