Endangered species Endangered species While protection for endangered wolves is still in question, a rare aquatic insect was denied endangered species protection this month. Its declining population is said to be related to fast-disappearing glaciers at a national park. On this Earth Day, we take a look at some animal species that have long been on the critical list. Pacific walrus These endangered marine mammals can weigh an astonishing amount and live in this ocean. Their numbers declined rapidly after they were heavily hunted for their blubber and ivory. Northern flying squirrel They are not capable of flight like birds, but the nocturnal Northern flying squirrel glides effortlessly between trees. Find out how far they can go. Where can they be found? Tiger A powerful predator, the tiger's six remaining species are facing extinction, and all are under protection.Yet an illegal act still threatens their existence. Polar bear The world's largest land carnivore is thre...