Spectator isn't a word usually applied to our sea lions, Zoe and Sierra. These two are most often seen moving around the New Balance Foundation Marine Mammal Center at top speed, whether they're zipping through the water, porpoising or slaloming down the ramp that leads to the behind-the-scenes area. But in the video below Zoe and Sierra prove there are lots of ways to add exercise to your day, even when you are being a spectator.