Sample: v2

SEA OTTER FUR: The sea otter has 42 hair follicles per sq. mm of skin. (A square millimeter is about the area of the tips of two mechanical pencil leads. This is true.) The sea otter gets the prize for the densest fur on earth. Each hair follicle contains 50 hairs. This gives it an amazing 1 million hairs per square inch! Their fur is so dense that water can’t touch the otters’ skin even when they go swimming.

SEA OTTER FUR: Ducks can sit on a lake in below freezing temperatures and not even feel the cold. This is in part due to the waterproofing oil that coats each individual feather. This coating keeps the freezing water from ever touching the skin of the duck.

SEA OTTER FUR: The insulation does not just protect the animals from the cold, but from heat as well. In 2013, scientists were studying brown fur seal pups. They were doing temperature readings and discovered that the outside of the fur heated to 205ºF.

SEA OTTER FUR: The internal temperature of the otter didn’t even register 1º (hotter) despite the fact that the outer fur soared in temperature.

FIBERGLASS: People often put insulation in their interior walls because it keeps sound from going through them as much. The air and the fibers act like a little wall to keep the sound waves from bouncing from one piece of drywall to another inside the wall.

GOOSEBUMPS: Goosebumps are caused by the flexed arrector pili muscles at the base of the tiny hairs on your skin. When the tiny muscles relax, they pull the hairs they’re attached to straight up. When they contract, the hairs lie down.

GOOSEBUMPS: To keep the hairs erect, the brain continues to send messages to the arrector pili by your sympathetic nervous system.

GOOSEBUMPS: If you hike through a forest on a cold day, stay away from the cold wind as much as possible. Take shelter amongst a grove of trees. Here the air is still and much warmer. Since cold moving air can take away from your body’s core temperature, the trees can help prevent this by acting as a barrier between you and the frigid wind.

GOOSEBUMPS: When you get goosebumps, it’s like you’re making a tiny forest of hair on your skin. The standing hairs trap a little invisible blanket of air around your exposed skin. This prevents some heat loss that you’d have if you were bare-skinned with no protection from the cold air always moving around you.

GOOSEBUMPS: When cats come home on a really cold night after roaming the neighborhood, they often look like big puff balls. The proxima pili muscles around hundreds of thousands of hairs make the cat’s fur stand straight up which creates big blankets of warm air around them.