This in turn enabled them to calculate how much energy bees burn in flight: an estimate of about 1.2 kJh-1. That figure may not mean a lot, so let me contextualise by saying that a running man uses up the calories in a Mars bar in about one hour. A man-sized bumblebee (which would, I admit, be pretty terrifying) would exhaust the same calories in less than thirty seconds. Hummingbirds are often thought of as having exceptionally high metabolic rates, but a bumblebee’s is roughly 75 per cent higher.
D. Goulson, A sting in the tale: my adventures with bumblebees (2013), 33
