(dramatic music) - [Shawn] What sea otters have in their favor is they just are have that incredibly cute round face with the small little tiny ears, just this fluff.

And that just really draws people in.

They're a combination to between a kitten and a puppy, wrapped up in this incredibly thick fur.

And then it's their playfulness as well.

People just really connect to that.

It reminds them of like a fuzzy baby, I think is what it is.

It's a fur party.

(Shawn laughs) (soft upbeat music) - [Narrator] Dr. Shawn Larson is the curator of conservation research at the Seattle Aquarium.

And part of her job is to work with one of the ocean's most charismatic and adorable creatures.

- I've been here since 1995 so going on 27 years.

I came into the aquarium not knowing anything about sea otters.

My background was in terrestrial wildlife.

so I studied big cats for my master's degree.

And she found herself a shell.

She's gonna get the last little bits.

And to me, sea otters are like sea cats.

Oh, and he's trying to steal it.

(Shawn laughs) They're just adorable, obviously.

But as I started studying them, I realized that they had many secrets to unleash and many stories to tell.

I'm still learning from them to this day.

- [Narrator] Shawn knows otters on an intimate level.

She studied breeding in captivity, their genetic diversity, and even rescued and rehabilitated pups.

She's also studied their signature feature, their fur.

Sea otters have a thick layer of fur that is the densest in the entire animal kingdom.

- Their fur is so dense that in some areas of their body, in a square inch about this big, they have up to a million hairs.

- [Narrator] Compare that to 100,000 hairs on the average human head.

- [Shawn] You can take all of your hair on your head and squish it down and it wouldn't be even close to the amount in one square inch of sea otter fur.

Oh, I missed tropical (indistinct) (Shawn laughs) It's so dense that the water that they swim in never touches their skin.

Essentially they're floating around in a little dry suit.

But that really, really thick fur is what almost drove them to extinction during the fur trade.

- [Narrator] The fur trade, at one time, driven by the demand for sea otter pelts, had a much bigger impact than just endangering these animals.

It spurred colonization by Europeans all of over north America, and especially the west coast.

This brought devastation and disease to indigenous populations who had coexisted with sea otters for generations.

By the time the fur trade sputtered out in the early 1900s, sea otters had nearly vanished from the earth.

- [Shawn] It is estimated that we lost 99% of the sea otters in the world to that fur trade because at that time, any fur coat that people wanted was a sea otter fur coat because it's just so incredibly thick and soft.

- [Narrator] Amazingly, otter populations in many parts of the world bounced back when humans decided it was more important to see them than wear them.

But recovery was slow in the Pacific Northwest - By the 60s, the sea otters had recovered from the fur trade in the Aleutian chain.

That was the success story.

Sorry, I'm excited 'cause we got otters.

Foraging already.

But the sea otters were still struggling to recover in California, in Washington, in DC, in other areas, because their populations were slow-growing, that Aleutian chain population which had been doing so well and was the success story, and was declining.

So we'll get everything set up, see if we can gather some data.

There we go.

They had lost 90% of their numbers.

So, going from about 60,000 animals to about 6,000.

So in the 90s, they were listed as endangered.

All right, miss Aubry, let's find us some otters.

(playful music) - [Narrator] Sea otters remain on Washington State's threatened species list.

But this healthy population off the Olympic coast plays a big role in the ecosystem.

Their presence can make all the difference for coastal biodiversity.

Shawn's observations in the wild help monitor the health of these vital marine ecosystems.

- The scientific community has learned a lot about what the world looks like without sea otters and with sea otters because of that fur trade and having many populations hunted to extinction.

In areas without the otters, there's just nothing there but urchins.

It's like the underwater landscape has been scoured clean with a pressure washer.

So the sea otters come in, knock back the urchins, the kelp could then regrow.

And then within a year or two, you had these beautiful canopy-forming kelp forests, you had more crabs, you had more clams, you had more fish, and it just became a more diverse and a more stable ecosystem.

The kelp is really a good carbon sink.

So the more kelp, the more carbon can be kept from the atmosphere.

So, it's not just for the sea otters population health, it's also for the health of the ecosystem.

Oh my gosh!

Okay, he just brought up a kelp crab.

He's scratching his back.

He's so cute.

Oh, no, he's handsome.

I'm sorry.

You're handsome.

(Shawn laughs) It just makes me happy watching them, period.

But then to know the role that they play in the ecosystem and how they can stabilize it makes me even more happy and grateful that they're there.

I'm just inspired by the otters and everything that they're showing us and that we're still learning about them.

Wow!

That was pretty incredible.

Okay.

I'm done.

(Shawn laughs) Yay!

They've taught me not to take myself so seriously and be joyful (laughs) because they play a lot.

And I'm inspired to go out and watch them because that really brings me joy.

So, I'll keep on watching sea otters as long as I can.