The Shimada family gathers around Paro, a cuddly, furry seal designed by Japanese roboticists to engage patients suffering from dementia--or in the Shimadas' case, to serve as a virtual pet. Its sensors allow it to discern the presence of people and respond to touch by wiggling its body and emitting seal-like cries. Its electronic brain has a rudimentary ability to learn words taught by its users and respond with sounds and movements. Some critics of social robots worry that the time spent with such devices could supplant interactions with real people, further distancing impaired people from society.

Compressed air flows beneath silicone skin, triggering actuators that raise her arms and lift the corners of her mouth into a demure smile. She seems to compose herself, her eyes panning the room where she stands fixed to a platform, tubes and wires running down through her ankles. She blinks, then turns her face toward me. I can't help but meet her--its--mechanical gaze. "Are you surprised that I'm a robot?" she asks.

It's not a vulture or crow but a Falcon--a new brand of unmanned aerial vehicle, or drone, and Johnson is flying it. The sheriff's office here in Mesa County, a plateau of farms and ranches corralled by bone-hued mountains, is weighing the Falcon's potential for spotting lost hikers and criminals on the lam. A laptop on a table in front of Johnson shows the drone's flickering images of a nearby highway. Standing behind Johnson, watching him watch the Falcon, is its designer, Chris Miser. Rock-jawed, arms crossed, sunglasses pushed atop his shaved head, Miser is a former Air Force captain who worked on military drones before quitting in 2007 to found his own company in Aurora, Colorado. The Falcon has an eight-foot wingspan but weighs just 9.5 pounds.