Sea otters have the densest fur of all mammals on earth. On average (don’t ask me who figured this out), for every single square inch on a sea otters’ body, there are a million hairs. That, along with a few other amazing little refinements, is what makes it possible for them to swim in the frigid waters they frequent. Now engineers are looking at how that could help wetsuit technology.
It’s pretty common for engineered equipment to mimic nature in some way, so a hairy wetsuit isn’t too far of a stretch of the imagination. Sea otters spend a lot of time grooming themselves, keeping their dense fur in perfect condition. While they swim, that fur traps air next to the sea otter’s body, and stops the cold water from getting the skin wet.
And so cute, too!
For years, researchers have studied how different surfaces react with water. Because of waters’ surface tension (the thing that makes it possible to fill a glass just a little bit over the rim) tiny bumps and ridges can almost act as a repellent. Flexible structures, though, like hair, haven’t been studied all that much. And sea otter fur is especially interesting. It’s so good at trapping air, that without it, the animal would look very different. “Without its air-trapping layer of fur, an otter would need a layer of blubber so thick it would end up the size of a seal,” said Heather Liwanag, a marine biologist at California Polytechnic State University in San Luis Obispo.
On the outside, they have a thick layer of guard hairs, which are oval-shaped. That helps them to all lie in the same direction when wet. The inner hairs have tiny scales on them, which enables them to lock together. When all the fur is working together, the sea otter has a flexible, soft shell that locks out water and holds in air. So far, researchers haven’t been able to mimic it perfectly, but they’re trying.
First, they made sheets of rubber covered with hundreds of small, rubber-filled tubes. Then they dunked them in the water until all the air between the tubes was forced out by the water. As one would expect, the longer and closer together the tubes were, the longer it took for the water to replace the air. If they’re able to mimic a sea otters’ fur just a little bit better, the wetsuits of the future might look a whole lot different.