How zebras, giraffes and other wildlife help stop rhino poachers
In Kruger National Park, South Africa, rhinos, zebras, giraffes, impalas and wildebeest have been fitted with GPS tracking transmitters. Their movements in response to humans trigger an alarm, so rangers can move quickly to stop poachers. Learn more in The Secret Knowledge of Animals, now streaming on CBC Gem and The Nature of Things YouTube channel.