Ollie, a three-month-old rescued sea otter, investigates a video camera at the Aquarium of the Pacific in Long Beach, California. The otter was stranded and rescued off Santa Cruz when she was a few weeks old. Picture: AP
Members of the gastropod class, finger-size nudibranchs live fully exposed, their gills forming tufts on their backs. (Nudibranch means “naked gill,” a feature that separates them from other sea slugs.).