becausepeople use them for fur hats and used to trade there skin
They were never part of the endangered species list. Actually Their Endagered in About 12 Areas.
In California, the southern sea otter is listed as threatened (not endangered).
The Otter is threatened and not yet endangered.
when you died
Orcas (killer whales) eat the sea otter which is partly why they are an endangered species.
It has resulted in rapid decline in otter population and the species has become endangered.
I wonder who told you that, in natural habitats, predators (killer whales) prevent overpopulation of their prey (sea otters). If you want to point fingers at the cause of the sea otter decline, point at hunters and poachers, because of them, many species have become endangered or extinct.
Extinct Steller's Sea Cow Bhaji River Dolphin Endangered Sea Otter Manatee
Because we kill otters river otters have made a comeback in most places,not endangered.
Because of habitat loss, pollution and hunting.
I think mammals... but I am not 100% sure...
The sea otter is a mammal and is a vertebrate.