Skin, Hair & Armor

What's 11 feet tall, 10,000 years old, and wears a skirt? The woolly mammoth... obviously!

During the dawn of the 20th century, explorers discovered 10,000 year-old mammoth hair in the Alaskan Arctic. These huge mammals developed thick layers of hair to protect their skin from frigid weather. Among the layers were 3-foot-long (90 centimeters) strands of hair covering the flanks and belly in a "skirt" like those on musk oxen living today.

Discovered in 1907 on an expedition in the Alaskan Arctic, this preserved mammoth hair is about 10,000 years old.
AMNH/D. Finnin

The woolly mammoth's coat seems like a fairly mild adaptation when compared to the Chinese pangolin, an endangered mammal living in the forests and grasslands of Central and Southeast Asia. When frightened, pangolins roll into a ball and, using strong muscles in their skin, raise their scales into a series of sharp blades. Their line of defense doesn't stop there--pangolins can target attackers with jets of foul-smelling liquid.
 
In fact, the evolution of mammalian skin has taken some pretty extreme turns - from the flexible, bony shells of the armadillo to the pangolin's scales to barbed quills of the porcupine.

Yes, the woolly mammoth wore a skirt. No, it wasn’t a fashion statement. The now-extinct mammal grew thick, three-foot long strands of hair around its flank and belly to protect it from arctic temperatures.
George Ksandr/Interfoto

To ward off predators, armadillos have a flexible, bony shell on their backs, the only group of living mammals to do so. Called a carapace, it is made up of bony pieces, or osteoderms, that grow from within the skin, with a covering of keratin scales.
iStockphoto

Pangolins are nearly covered by scales—only their bellies and throats are bare. Made from keratin, pangolins’ scales protect them from predators’ bites, and those of their own prey—ants and termites.
Keren Su/Corbis

If a porcupine’s barbed quills lodge in an attacker’s body and pierce an organ, they can kill.
J&C Sohns/AGE Fotostock

Fun Facts

• A hedgehog has up to 16,000 spines. Males "rattle" these in their mating "dance." Adult hedgehogs sometimes lick or "anoint" their spines with frothy saliva. Scientists still don't know why.
• The naked mole rat is nearly hairless and lives in underground colonies. These African rodents warm themselves in tunnels that lie close to the surface and are heated by the sun.
• An amazing array of mammalian body parts are made from keratin, a protein found in the skin. These include hair, quills, scales, spines, horns, hooves, claws, whale baleen, and the fingernails and toenails of primates, including humans.