GELLERMAN: Long before there were snowmobiles and airplanes, sled dogs were one of the main methods of transportation in the Arctic regions of the world. Dogs mushing over frozen ground are still very much in evidence today but as writer Mark Seth Lender found out, the job, and even the dog itself, has changed.

LENDER: A thousand years of dogs: running pressure ridge and ice ridge, skirting every crevice, loping frozen tundra through permanent day and the long months of near dark. They are a special breed.

Their sense of snow; their sense of smell; long hours without shelter in wind that freezes human flesh solid as a wall of ice and the dogs did not lie down, not once. Forward. Panting. Steady on broad feet on short legs made to endure, sure footed as Magnetic North.

Behind the loaded sled, following, Inuit come. Drawn toward the lodestone of Viking iron offered in trade for meat, for fat, for furs. And sled dogs led them on that journey - every inch - and by heart and will and sinew allowed Inuit to stay.

Now this canine Continental Drift is done, what will become of Arctic in a civilized imagination? As the Arctic melts away the Inuit dog remains. Bred now for speed, racing the leads that crack the shelf ice like liquid lightning; across bare snow in a blizzard minus 40 below, their job is not to carry but to win, and keep alive at least the sound, that deep-throated growl, the barking howl of the team.

LENDER: In dappled winter dark, light-echo of a sunrise that never seems to come, what Arctic Dreams do Inuit Elders dream?

GELLERMAN: Mark Seth Lender is a regular contributor to Living on Earth. To see some of Mark’s sled dogs photos, go to our website, LOE dot org.