Sebastian Kennerknecht / Sea Otter (Enhydra lutris) veterinarians Mike Murray and Marissa Viens performing surgery on rescued otter as volunteers look on, Monterey Bay Aquarium, Monterey Bay, California

Chris Gomersall / Eye spot on wing of owl butterfly (Caligo genus)

Pete Cairns / Close-up of Common alder leaf {Alnus glutinosa}, Scotland, UK.

Sebastian Kennerknecht / Sea Otter (Enhydra lutris) veterinarians Mike Murray and Marissa Viens performing surgery on rescued otter, Monterey Bay Aquarium, Monterey Bay, California