Pair of Huskie Pups, Herbert Island, Greenland, 2006

These young pups on Herbert Island, Greenland, will grow up to be powerful, thick-furred sled dogs conditioned to survive long periods of exertion in subzero temperatures. A hardy breed descended from canines that accompanied immigrants who traveled from Siberia to Greenland some 5,000 years ago, Greenland dogs pull sleds that weigh upwards of a thousand pounds (450 kilograms) in temperatures near minus 70 degrees Fahrenheit (minus 57 degrees Celsius).

(Photo shot on assignment for, but not published in, "Last Days of the Ice Hunters," January 2006, National Geographic magazine)