by Valerie Shore, marine naturalist
They’re furry, feisty and high-maintenance. They’re also absurdly—dare we say it—cute. Their teddy-bear like appearance and boundless energy can enchant even the most hardened human observer.
We always get excited when we see a sea otter on our whale watching tours from Victoria, although they aren’t common in the Salish Sea. Whenever we visit Race Rocks Ecological Reserve, we look for a male sea otter nicknamed “Ollie” who has been living there for several years.
Sea otters are the largest member of the weasel family and are well adapted for life in the harsh North Pacific—in many unique ways. They’re also an essential part of a healthy coastal ecosystem. We know that because we almost lost them forever—and learned some valuable ecological lessons along the way.
Let’s get better acquainted. Here are nine things about sea otters that may surprise you.
- THEY’RE NOT RIVER OTTERS
We mention this first because, well, there seems to be some confusion about this. People see an otter in the sea and therefore it must be a sea otter, right? Um, not likely.
Just to mess with our heads, river otters can also live in the ocean. In the Salish Sea, they’re the sleek, petite otters we commonly see swimming along shorelines, scurrying over rocks and boats, and crunching shellfish and crabs on the dock in front of us as we grope for our cell phone cameras.
On the other hand, sea otters eat, sleep, groom, mate and give birth at sea. They prefer sheltered bays and reefs along the rugged outer coast of North America. They rarely come ashore and when they do they’re pretty clumsy. You try walking on big, paddle-shaped hind flippers and you would be too.
Sea otters are also larger (up to 90 lb.), have shorter and thicker tails, and spend most of their lives floating on their back, even when eating.
- THEY’RE FLOATING FUR COATS
You’d think a warm-blooded animal that spends its entire life in a very cold ocean must have an incredibly thick layer of blubber to stay warm. But you’d be wrong. Sea otters don’t have blubber like seals and sea lions. Their superpower is their fur—the densest in the animal kingdom.
An adult sea otter has roughly 100,000 hairs per square centimetre or about one billion hairs in total. By comparison, we humans have 100,000 on our entire heads, if we’re lucky!
This furry luxuriance is organized into two layers—long guard hairs and soft dense underfur. The guard hairs are waterproof, while the underfur traps a layer of air to provide additional insulation. As long as the otter keeps its fur clean, its skin never gets wet!
- THEY’RE OBSESSIVE GROOMERS
And there’s the rub. While the sea otter’s plush fur coat is its best weapon against hypothermia, it’s also its biggest vulnerability. If that fur gets dirty or gets clogged with nasty stuff like oil then the otter will get wet and die from the cold.
Which is why a sea otter spends a big portion of its day grooming—rolling and somersaulting as it rubs, combs and squeezes every inch of fur with its paws and tongue. While doing this, it traps air bubbles in its dense fur fibres, keeping its skin dry and helping it to float like a cork.
How does the otter clean the fur on its back? Easy peasy. They’re essentially otter skeletons in a fur bag. They can roll inside their own baggy skin to get at those hard-to-reach places. Their skin is so elastic that a pelt can be stretched to almost 150 per cent of its actual body length!
- THEY’RE BINGE EATERS
Thick fur is nice but it’s still not enough to keep a sea otter warm. To keep its inner furnace burning brightly the otter has to eat an astonishing 25 per cent of its body weight every day!
And eat they do—with gusto. Their seafood smorgasbord includes more than 100 types of marine invertebrates such as crab, clams, abalone, octopus and sea urchins. Some otters eat so many urchins that their teeth, skulls and skeletons are stained purple!
Sea otters have poor underwater vision but that doesn’t slow them down. Their ultra-sensitive whiskers can locate prey hiding in the kelp. They use their strong front paws to poke among rocks and crevices and dig on the seafloor. If they find multiple goodies per dive, no problem. They stuff them in the loose fur under their armpits, like a shopping bag, and head for the surface!
- THEY’RE TOOL USERS
Back at the surface, the otter flips to its customary position—on its back—and using its chest as a dinner plate, makes easy work of almost anything on the menu.
For the really tough shells like clams and mussels, sea otters have another trick up their furry sleeves. They’ll grab a rock from the seafloor, bring it to the surface and use it to bash the bivalve into edible bits. They’re one of the few mammals other than humans known to use tools.
They’ll also use stones to pry abalone off rocks underwater, which is pretty impressive when you consider that an abalone can exert suction equal to about 4,000 times its body weight. Again, no problem. Holding a stone in both paws, the otter will doggedly pound the side of the abalone shell at the rate of 45 blows in 15 seconds!
- THEY’RE SOCIABLE, SORT OF
Eating is serious business for a sea otter so they tend to forage on their own. But on some parts of the coast they gather in large groups known as rafts to rest and socialize. Males and females usually raft apart. Rafts can be seen further up the west coast of Vancouver Island and on BC’s central coast. The largest raft ever recorded contained up to 2,000 sea otters!
A raft of sleeping sea otters is an unforgettable sight. They float on their backs (of course!), hind flippers folded over their bellies, and forepaws held up in the air to conserve heat. Some rest with their forepaws over their eyes, some with their chin on their chest. Often, they wrap themselves in kelp as anchors against the current and rolling swells!
In expanding populations, which is the case in BC, male sea otters are the first to investigate new, prey-rich areas. Ollie the sea otter at Race Rocks is one of these explorer males. He’s found a great spot to put down roots and he’s no doubt hopeful the girls will arrive soon. He’s still waiting.
- THEY’RE GREAT MOMS
Yes, we’ve skipped the courtship part because, to put it delicately, there’s no such thing as sea otter romance. Mating is not pretty, at least not for the female who often ends up with a bloody nose or worse from her over-eager suitor. It’s the dark side of sea otter life.
But let’s not dwell on that. Let’s focus instead on the kitten-sized fuzzball that appears several months later. Mom dotes on this helpless ball of fluff for the next six to eight months—nursing, feeding, grooming, protecting and patiently teaching it how to be a successful sea otter. All the while providing it with a comfy bed on her chest!
Devoted as she is, mom must leave her baby on the surface while she does short dives for food. Often, she wraps it in in kelp so it will stay put. It’s a risky time as the pup bobs like a cork, vulnerable and impatient. And it’s vocal. Very vocal. It shrieks like a banshee so that mom can find it again in the swell. Those screams can be heard up to a kilometre away!
How adorable are sea otter pups? Meet “Hardy” rescued by the Vancouver Aquarium in 2017.
Watch a mom and newborn pup at the Monterey Bay Aquarium.
- THEY CAME BACK FROM THE BRINK
Remember that plush fur coat we talked about? It’s great for keeping sea otters warm. It was also great for making lots of money, as 18th and 19th-century fur traders quickly discovered. Hundreds of thousands of sea otters were slaughtered throughout their range, which used to span the Pacific Rim from Baja California to northern Japan.
By the time sea otters were protected by most countries in 1911 they’d been wiped out from much of their range. Where there were once as many as 300,000 they’d dwindled to fewer than 2,000.
Even then, there was no respite for BC’s sea otters. Sporadic hunting continued and the last one was killed in 1931. For decades, the BC coast was devoid of sea otters and there were serious ecological consequences (see below). That’s one reason why, from 1969 to 1972, a total of 89 sea otters were whisked out of Alaska and deposited in Checleset Bay on the west coast of Vancouver Island.
The descendants of those Alaskan immigrants have since thrived. There are now more than 6,000 sea otters at various spots along BC’s outer and central coast. Their range continues to expand. Ollie the sea otter is an Alaskan descendant, either from further up Vancouver Island or from Washington State where a similar transplant took place around the same time.
- THEY’RE GUARDIANS OF THE KELP
Why go to all that trouble to bring sea otters back? Turns out that sea otters and kelp forests have an arrangement. They need each other. And nearshore ecosystems need them to be in perfect harmony.
It’s a simple lesson in interconnectivity. When the sea otters vanished, one of their favourite foods—sea urchins—went on the rampage. What do sea urchins like to eat? Kelp. Without the sea otters to keep them in check, urchins and other grazing invertebrates can turn flourishing kelp forests into underwater wastelands called urchin barrens.
Healthy kelp forests are a very good thing. They’re the marine version of a rainforest, providing food and shelter to a vast assortment of plant and animal life, boosting diversity and creating richer habitat for fish (some of which we like to eat!). They also reduce coastal erosion and absorb significant amounts of harmful carbon dioxide from the atmosphere.
As sea otter populations have rebounded, so has the health of kelp forests. This is why sea otters are referred to as a keystone species—they have a huge, positive influence on their environment! It’s just another reason why we love sea otters so much!
We hope you can book a tour with us soon and see one of these charismatic marine mammals for yourself!