Scientists have long puzzled over how pterosaurs became the first vertebrates to master flight. Some pterosaur species, such as the Quetzalcoatlus were the largest known animals to ever take to the skies, with wingspans of over ten meters (on par with military aircraft like the Spitfire). My team's new study may help solve the evolutionary mystery, revealing how a vane on the tip of their tails may have helped these ancient animals fly more efficiently. Our findings are published in the journal eLife.