The heaviest-ever flying bird was Argentavis magnificens, which lived six million years ago. It had a similar height and weight to an adult human, with a wingspan of six metres. These wings would have been too large and hefty for continuous flapping, so it probably flew more like a glider, taking off by running downhill into a headwind. We’d have to adopt a similar flying style.
Muscles and bones
To flap these wings, we would need pectoral muscles twice the size of a pro bodybuilder’s. Our bones would be lighter and therefore weaker, so we’d need to strengthen our collarbone by fusing the clavicles into a wishbone. We’d also need a ‘keel’ bone protruding down the centre of our chest, to allow the pectoral muscles to attach further from the shoulder, increasing their leverage.
Even with all this, we probably couldn’t fly unaided. Birds have a more efficient one-way airflow through their lungs to get more air with each breath, and their muscles have extra oxygen-carrying proteins. Their nervous system runs faster to give them the reaction times needed for in-flight manoeuvring. We would need help from an oxygen cylinder, and a flight computer with a heads-up display.
Read more thought experiments:
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- What would living on Mars do to my body?