Sea Otter
Sea Otter Facts
| Size | 40-47 inches (100-120 cm) |
| Speed | 5-7 mph (8-11 km/h) |
| Weight | 28-88 pounds (13-40 kg) |
| Lifespan | 8-13 years |
| Food | Sea urchins, starfish, molluscs |
| Predators | Sea lions, orcas, sharks |
| Distribution | Worldwide except Australia and Antarctica |
| Habitat | Sea, coast |
| Order | Carnivores |
| Family | Martens |
| Subfamily | Lutrinae |
| Scientific name | Enhydra lutris |
| Characteristics | Marten, which lives exclusively in the sea |
Main Characteristics
Sea otters are martens that spend their entire lives in the sea. They're perfectly adapted to life in water thanks to their thick fur, webbed feet and streamlined body. They are famous for using rocks to crack shells and holding hands in the water. They're closely related to the North American river otter.
Distribution and Habitat
The sea otter is the only species of otter that lives primarily in the sea. It was once widespread on the coasts of California and Japan. Today it lives mainly on the coast of the Bering Sea in the North Pacific.
Life Style
Sea otters are active during the day and at night. Unlike other marten species, they aren't solitary animals. They gather in loose groups and hold on to each other while they sleep. They primarily inhabit the sea. To keep their body temperature stable in the cold water, they need a lot of food. That's why they spend most of their time looking for prey.
Anatomy and Appearance
Size and Weight
Sea otters are significantly larger and heavier than river otters. They reach a body length of 47 inches (120 cm). Their tail is 12 inches (30 cm) long. The males weigh 48-88 pounds (22-40 kg) and the females 28-72 pounds (13-33 kg). The males are slightly larger and heavier than the females.
Webbed Feet
Sea otters have webbed feet so they can swim faster.
Fat Layer
Sea otters lack the thick layer of fat known as "blubber", which is common in aquatic mammals. Instead, they rely on their dense fur to maintain warmth.
Whiskers
Otters have long whiskers around their mouths. When the water is murky, they use them to detect prey.
Pouches
Sea otters have loose skin under their forearms. It works like pouches or pockets, allowing them to carry food and their favorite rocks. This is quite similar to how hamsters store food in their cheek pouches.
Fur
Sea otters have a dense undercoat and a protective top coat. The top coat consists of long, waterproof hairs. In the undercoat, small air bubbles get caught. They form a warming layer and ensure that the animal stays dry. Sea otters have the thickest fur of any mammal. They have up to 1 million hairs per square inch (100,000-400,000 per square centimeter). For comparison: a human has up to 150,000 hairs - but not per square inch, but in total on the entire head.
Diet
Sea urchins make up 70% of a sea otter's diet. The remaining 30% include starfish, mussels, crabs and sea snails. They open the hard shells of their prey, they use a rock that they store in a pocket of loose skin located under their arms.
Behavior
Playfulness
Sea otters are very playful, curious and intelligent. They love lounging on their backs, spinning around, playing catch, and they always have a favorite rock they take everywhere. It is a rock that they use to break open shells.
Grooming
Sea otters have waterproof fur, and to keep it that way, they clean it every day - for several hours. They use their claws to scratch it and spin around a few times to clean off any leftover food from their fur.
Social Behavior
Sea otters form small groups of 10 to 100 animals. The groups are separated into females and males.
Why Do Sea Otters Hold Hands?
Sea otters hold hands to keep each other warm and prevent drifting away while sleeping.
Senses and Abilities
Swimming
Sea otters are excellent swimmers. When they are not paddling, they float on the water surface. The air that gets caught in their undercoat gives them buoyancy - like a swimming ring.
Diving
Sea otters can hold their breath underwater for up to five minutes. Before they dive, they close their ears and nose to keep water out.
Salt Water
Sea otters can handle salty seawater since their large kidneys help them get rid of the excess salt.
Intelligence
Tool Use
Sea otters are among the rare animals that utilize tools. They have this ability for much longer than other marine animals, such as dolphins. Researchers believe that they have been using tools for thousands, if not millions, of years.
• Breaking Open Clams
Sea otters have a smart way of breaking open clams. They float on their backs, balance a rock on their chest, and then smash the clam against it, using the rock as a makeshift anvil or hammer.
• Seaweed
Sea otters cleverly use seaweed to wrap up crabs they catch, ensuring the crabs can't get away.
Enemies and Threats
Natural Enemies
Sea otters are preyed upon by orcas, sea lions and sharks.
Human Impact
The biggest threat to sea otters comes from human activities. Oil spills happen repeatedly in the ocean. The oil clumps the fur, making it lose its waterproof quality. They also take in the harmful oil through water and food sources. Plus, they're hunted for their fur, which is why they're considered an endangered species in most countries around the world.
How Many Sea Otters Are There Left?
According to an IUCN estimate, there are around 130,000 sea otters left worldwide. Their numbers have declined significantly over the last two decades - in some areas they have almost disappeared completely. Their status is “endangered”.
Importance for the Ecosystem
Sea otters play a crucial role in safeguarding kelp forests by preying on herbivorous sea urchins, which consume the kelp. They're considered a keystone species because, despite their relatively small number, they have a large influence on the balance and biodiversity in their habitat.
Reproduction
Sea otters mate between summer and fall. The gestation period lasts 6-9 months. The babies are born with their eyes open and are carried on their mother's belly for the first few weeks. They have a special fur that allows them to float on the surface of the water, because they can't yet swim. While the mother searches for food, it wraps its babies in seaweed, so they don’t get “lost”. When the offspring are around two months old, they can swim and dive independently. After 6-8 months they are independent of their mother.
The Sea Otter Is Related To:
- Badger
- Marten
- Polecat
- Sea Otter
- Weasel
- Wolverine
Animals in the Same Biome:
- Albatross
- Beluga Whale
- Blue Whale
- Orca
- Sea Urchin
- Seal
- Sea Lion
- Starfish
- Walrus
