World Otter Day © Donald M. Jones/Minden Pictures
Watching sea otters playing in the water is always a treat. But while they look cute, these furry critters are also the top predators in their food chain, "otterly" vital to keeping ecosystems in balance. Sea otters eat sea urchins and without them, sea urchins spread across the sea floor, destroying crucial kelp forests which provide food and shelter for many other aquatic animals. Unfortunately, sea otters are one of five otter species listed as endangered by the International Union for Conservation of Nature. Five others are listed as near-threatened and two as vulnerable. Of the 13 otter species worldwide, only the North American river otter’s population is considered to be stable. On the last Wednesday in May, World Otter Day seeks to raise awareness about the threats to otters, and how to protect them.