Many mammals that swim in icy seas rely on blubber, like walruses, wales, and porpoises. But how does the adorable sea otter (Enhydra lutris) make it through the winter, without that layer of fatty insulation?

That’s the question explored in the latest episode of Deep Look, a series from KQED that explores the natural world by looking at the very small. In this episode, they take a close look at the otter’s fur, which it turns out is pretty special.

Sadly, sea otters are considered endangered by the International Union for Conservation of Nature (IUCN). Once over-hunted for their fascinating fur, today the sea otter’s biggest threat is oil spills, according to the IUCN. Oil interferes with the fur’s ability to keep the otter warm, in addition to making them sick from ingesting its toxins.

Sea Otters play an important role in the ecosystem, and may even be mitigating some of the harmful environmental impacts of human activity. Otters help protect kelp from sea urchins, which in turn slows global warming. They’re also thought to combat harmful agricultural run-off. So, it’s easy to make the case for protecting otters because they’re adorable, but we also need to care about their conservation because a declining otter population could also have cascading impacts on other species.

You can check out more episodes of Deep Look on KQED.