Here’s one word to describe the Northern California coast: COLD.
If you or I were in those waves without a wetsuit right now we’d get hypothermia in ten minutes.
But sea otters have figured out how to survive here, which is amazing.
Especially when you consider that this little guy has to maintain an internal body temperature around 100 degrees Fahrenheit,
almost twice as warm as the water he’s swimming in.
当然 鲸鱼和海狮都可以做到这一点 可那些哺乳动物已经经历几千万年
Sure, whales do it. Sea lions do it. But those mammals have had tens of millions of years
to adapt to life in the ocean.
Evolutionarily speaking, sea otters are newcomers…
land animals that waded into the ocean a mere couple of million years ago.
Unlike other ocean mammals, they have no blubber.
And they’re small, meaning they are constantly losing heat.
Their ace in the hole– is fur.
Sea otters have the thickest fur on the planet. Up to a million hairs per square inch.
It’s what keeps them alive.
但这致密的毛皮也导致他们被杀 回溯到19世纪 海獭被大肆捕杀
It also almost killed them — back around the 19th century sea otters were hunted nearly
to extinction to make hats and coats.
But it’s not really the fur, per se, that keeps the otter warm. It’s air.
毛皮能把空气吸进毛里 形成一个保温防护层 就像一条羽绒被盖在身上
Fur works by trapping air near the skin’s surface, like a down comforter.
由于海獭的毛皮致密 所以基本可以防水 你可以看到临近表皮 它的毛皮是干的
Sea otter fur is so dense it’s basically waterproof. You can see how dry it is close to the skin.
That layer of air gives the otter’s fur a glossy look
as it tumbles through the water.
那小海獭呢 它们的毛皮也可以吸收空气 帮助他们在水面浮潜
Baby sea otters? Their fur traps so much air that they bob at the surface
their fluffiness makes them buoyant. That is, until they shed the pup fur and learn to dive.
This excellent insulation comes at a price.
Every time a sea otter dives, some of the air in their fur gets forced out.
看见那些气泡了么 当海獭准备再次潜水 就会吸取更多的空气进入
See those bubbles? And so the otter has to groom himself all over again, to pump more air in.
Let’s take a closer look at this fur.
As you can see, sea otter fur is actually made up of two kinds of hair:
under fur, the insulating part, and those longer, protective guard hairs.
Under a microscope, you can see how the individual hairs are scaly and rough.
That roughness is important.
Those barbs on the hair shafts let the fur mat together.
That’s what traps the air in.
相比而言 有一种小狼 当然它们并不住在冰冷的海洋里
For comparison – here’s a coyote. Coyotes, of course, don’t live in the freezing ocean,
and their hairs don’t have the barbs.
毛发让它们可以在陆地上也保持温暖 可在海洋里 他们就不能依旧保持干燥了
Their fur keeps them warm on land, but they wouldn’t stay dry in the ocean.
In a lot of ways, otters have more in common with land animals.
But many years ago, otters took an evolutionary leap into these icy waters.
And today they’re making it work.