Togo.

Don't you dare ever forget how rad Togo was.

From the Wik:
"Togo was the sled dog who led Leonhard Seppala and his dog sled team as they covered the longest distance in the 1925 relay of diphtheria antitoxin from Anchorage to Nome, Alaska, to combat an outbreak of the disease. The run is commemorated by the annual Iditarod dog sled race."
Balto may have been leader of the final sled team but Togo did most of the badass work in the 1925 serum run to Nome, Alaska.
Seriously, don't forget about Togo or his badassness.