Enhydra lutris

One of the most remarkable aspects of the Northeast Pacific’s marine mammals is the outsized role they play in shaping their environment. Once hunted to the brink of extinction, their return has set off a cascade of ecological changes that continue to unfold today.

Among these keystone species is the sea otter, whose insatiable appetite and playful nature make it one of the most captivating creatures to encounter. This artwork is inspired by my photograph of the sea otter below:

February 2020: A lone sea otter rests in a bed of kelp off a popular beach in Monterey, California. Given restrictions on approaching marine mammals, this photo was taken some distance away and is heavily cropped.

📖 Description 📖

Sea otters hold the title of the smallest marine mammal on the planet, yet they are among the most ecologically influential. Unlike other marine mammals that rely on blubber for insulation, Sea otters depend on the densest fur of any animal to keep warm in frigid waters.

They spend their entire lives at sea, rarely venturing onto land. From feeding and grooming to sleeping while floating on the surface, every aspect of their existence is tied to the ocean. Despite their small size, their presence has an outsized impact on coastal ecosystems, shaping the underwater world around them.

🌎 Distribution 🌎

Sea otters are found along the Northeast Pacific, with their range historically stretching from Japan, through the coasts of Russia and Alaska, and down to Central California. Their populations were once nearly wiped out due to the fur trade, but conservation efforts have helped them recover in many areas.

There are three recognized subspecies of Sea otter, each occupying a distinct part of this range:

Northern sea otter (Enhydra lutris kenyoni) – Found along the coasts of Alaska and down into British Columbia and Washington. This subspecies has the largest population and continues to expand its range.
Southern sea otter (Enhydra lutris nereis) – Also known as the California sea otter, this subspecies is found along the central coast of California. Unlike their northern relatives, they have not fully recolonized their historic range and remain a threatened population.
Asian sea otter (Enhydra lutris lutris) – Native to the coasts of Russia and northern Japan, this subspecies has a more fragmented distribution, with populations in the Kuril Islands, Kamchatka Peninsula, and the Commander Islands.

Each of these subspecies plays a vital role in maintaining the health of their respective marine ecosystems, particularly in kelp forests and seagrass beds.

🌊 Habitat 🌊

Sea otters in British Columbia primarily inhabit rugged, wave-exposed outer coasts and remote island chains, where they thrive in shallow marine environments rich in kelp forests, eelgrass beds, and rocky reefs. These habitats provide shelter from predators like Orcas and sharks and serve as important resting and foraging grounds.

Sea otters typically dive to depths of around 30 meters in search of food, although they are capable of diving deeper if necessary. Some individuals have been recorded diving as deep as 40 meters. However, they generally stay at shallower depths, where food is abundant.

Depth of suitable habitat for the Sea otter, ***Enhydra lutris.*** Suitable habitat depicted in red. Not to scale.

Unlike the river otter, which can travel between land and water with ease, the Sea otter is fully marine and spend almost their entire lives in the ocean. They prefer areas with complex underwater structures, such as rocky outcroppings and kelp beds. The kelp also serves as an anchor—otters will wrap themselves in the fronds while they sleep to prevent drifting away with the currents.

🦀 Diet 🦀

Sea otters have a high metabolism and must consume around 25% of their body weight in food every day to sustain their energy needs. As opportunistic predators, they feed on a variety of marine invertebrates, with their diet primarily consisting of sea urchins, crabs, clams, and other shellfish. Like many other species, Sea otters will feed on the most abundant supply of food in the region, maintaining the balance of coastal ecosystems.

Unlike most marine mammals, Sea otters use tools to access their food. They are known for their remarkable ability to crack open hard-shelled prey using rocks, which they keep nestled in the loose skin folds under their arms. They will repeatedly strike their shelled-prey against their favourite rock until it cracks open.

April 2024: A Red rock crab patrolling the seafloor in search of food. This species is one of many that are targeted by Sea otters.

The disappearance of the majority of Sea otters and Sunflower sea stars has had catastrophic consequences for kelp forests and eelgrass beds. Their favourite foods, including Green sea urchins and Purple sea urchins, no longer have any major predators, causing an explosion in their population.

🦦 Life Cycle 🦦

Sea otters give birth to a single pup after a 6-month gestation period, typically between November and May. Newborn pups are entirely dependent on their mothers for warmth and survival, as they cannot dive or regulate their body temperature. The mother keeps her pup close, ensuring it stays dry and warm by floating on her chest.

December 2025: Two sea otters bob along in the surf along the shoreline of San Joseph Bay on Northern Vancouver Island. Image is once again heavily cropped due to the distance these otters were photographed.

Pups are weaned around 6 months but often stay with their mothers longer to learn essential skills like diving and foraging. Sea otters reach sexual maturity at 3 to 5 years of age, and mating occurs year-round [1].

In the wild, sea otters can live up to 15 to 20 years, though many face threats from predators, disease, and environmental hazards, making their life expectancy variable. Their life cycle is closely linked to the health of their coastal habitat and food availability.