Why Do Old People Get So Hairy?

You've seen it at the local pool, at the beach, or even on your own grandpa. Old grizzled men with enough back hair to knit an afghan. Rampant tufts of hair springing out of dark nasal and ear cavities and eyebrows that look Cro-Magnon. What causes hair to grow everywhere but the head as we age?

Scientists don't exactly know what causes hair to sprout excessively from places like the ears and nostrils but Dr. David Liebovitz, an associate professor of Medicine at Northwestern University, guesses that it has to do with hormones and the lifecycle of hair.