Thousands of emperor penguins waddling around Antarctica have a stalker: A yellow rover tracking their every move. ECHO is a remote-controlled ground robot that silently spies on the emperor penguin colony in Atka Bay. The robot is being monitored by the Single Penguin Observation and Tracking observatory. Both the SPOT observatory, which is also remote-operated through a satellite link, and the ECHO robot capture photographs and videos of animal population in the Arctic. The research is part of the Marine Animal Remote Sensing Lab (MARE), designed to measure the health of the Antarctic marine ecosystem.