Around the world, many pets and working animals are microchipped. It's a simple process: A tiny transponder with an identification number is enclosed in a rice-grain-sized cylinder and injected under the skin, so that if an animal is lost it can be identified.

But electronic chips can do a lot more than hold an ID number. What if we could track a lost animal's location? Monitor a dog's heart rate after a medical procedure? Track the breathing rates of cattle and their calves on a livestock farm?