It's not that they can't. They just don't need to, says Mike Murray, a veterinarian at the Monterey Bay Aquarium in California. Birds have the anatomical and physical ability to pass gas, he explains, "but if I saw gas in a bird's gastrointestinal tract on an x-ray, I'd suspect that something abnormal was going on in there."
Five amazing, clean technologies that will set us free, in this month's energy-focused issue. Also: how to build a better bomb detector, the robotic toys that are raising your children, a human catapult, the world's smallest arcade, and much more.