How Much Hair do Sea Otters Have?

With about 1 million hairs per square inch (per 6 square cm), sea otters have more hair per square centimeter than humans do on their entire heads. Humans have an average of 100,000 hairs on their heads and an additional 5 million on their bodies, but sea otters can have as many as 800 million hairs. Their incredibly dense fur serves to keep the otters warm and dry, and it provides the otters with four times the insulation that fat or blubber would. If the fur becomes dirty or slicked with oil, however, its insulating ability is lost, which is why otters are so affected by pollution.

More talking points about otters:

• Although sea otters are the smallest marine mammals, they can grow to be as long as 5 feet (about 1.5 meters) and weigh as much as 70 pounds (about 30 kg).


• Sea otters are extremely sociable, and they often float together in groups of as many as 100 otters, called rafts.


• Sea otters are one of the animals that use tools the most. Not only do they use rocks to bash open shellfish, sea otters also wrap themselves in blankets of seaweed for extra insulation while they sleep.

Frequently Asked Questions

How dense is the fur of a sea otter?

Sea otters boast the densest fur in the animal kingdom, with an astonishing 600,000 to 1,000,000 hair follicles per square inch. This dense fur is essential for their survival, as it traps air and provides insulation in the cold waters of the Pacific Ocean where they reside.

Why do sea otters have such dense fur?

Sea otters have evolved to have dense fur as a means of thermoregulation. Unlike other marine mammals, they lack a blubber layer for warmth. Their fur traps air close to the skin, which acts as thermal insulation, keeping them warm in chilly waters. This adaptation is crucial for their survival in their aquatic habitat.

How do sea otters maintain their fur?

Sea otters engage in meticulous grooming to maintain their fur's insulating properties. They spend a significant portion of their day cleaning and fluffing their fur to ensure it remains waterproof and air-trapping. This grooming also helps to distribute natural oils throughout their coat, which aids in waterproofing and overall fur health.

Can sea otters get cold if their fur is damaged?

Yes, sea otters can suffer from hypothermia if their fur is damaged or contaminated by oil spills, as this affects the fur's ability to trap air and insulate. It's vital for their fur to remain clean and well-groomed to prevent cold water from reaching their skin and causing a drop in body temperature.

What role does a sea otter's fur play in buoyancy?

The trapped air in a sea otter's fur not only provides insulation but also contributes to buoyancy. This helps them float and reduces the energy required to stay at the water's surface. Consequently, a well-groomed, air-trapping fur coat is essential for both warmth and efficient swimming.

How does the fur density of sea otters compare to other animals?

When compared to other animals, sea otters have a remarkably higher fur density. For instance, humans have about 100,000 hairs on their entire head, while a sea otter has up to 1,000,000 hairs per square inch of their body. This extreme density is unmatched in the animal kingdom and is a unique adaptation of sea otters.