Sea otters are said to blow into their fur to keep buoyant.?

Question

where can I find info stating this fact? My son thinks I'm crazy, and wrong.

Answer 1

Sea otters have one of the thickest fur coats in the animal kingdom.
An adult pelt contains between 800 million to one billion individual hairs (roughly 100,000 or more per square cm).
Their fur is composed of two types of hair: long, sparse guard hair and soft, dense underfur, or pile hair.
Sea otters depend on their fur to keep them warm, as they have no insulating blubber layer. It is critical that sea otters keep their fur clean to maintain an insulating air layer between the water and their skin. Adults spend 15 percent or more of their day grooming their fur by licking and blowing into it.
At birth, a newborn sea otter’s coat, called a lanugo, acts like a life preserver and keeps the baby floating at the water’s surface. It takes at least two months before the “extra-buoyant” lanugo is fully shed. Only then can the pup dive.

Answer 2

Sea otters depend on their fur to keep warm. Their fur is the densest fur of all the animals. There may be up to 1 million hairs per square inch (150,000/cm2). That's more hairs than you have on your entire body! But even with such thick fur, it takes an effort to keep the otter warm. The sea otter spends hours each day grooming its fur. The otter needs to squeeze any water out, and to blow air into the fur. The air makes the fur waterproof, so that the otter's skin can stay dry and warm.

Answer 3

The answerer above is absolutely correct - the air doesn't keep them afloat, it helps insulate them from the cold of the ocean waters.

If you want proof there's some very nice video of this in the BBC DVD of the Life of Mammals TV documentary series. You can get it from your library or buy. The whole series would be great viewing for your son anyway.

Answer 4

You're right.

I'd recommend the "Life of Mammals" DVD where David Attenborough actually says that explicitly. :)