A delivery system built for snow
Where winter snow made ordinary road travel difficult, a sled could keep mail moving without a cleared road beneath it. Reindeer supplied the pulling power, while the runners of the sled slid over the snow and carried the bags behind the animals. Their broad, spreading feet helped them stay on top of soft snow rather than sink as deeply, and their hooves could grip the surface as they walked.
That combination mattered: the animal handled the uneven route, and the sled turned its effort into a way to move cargo. It was a practical answer to a landscape in which a wheeled vehicle might struggle to make progress.
Fuel that could forage
The advantage was not just traction. A delivery vehicle normally needs fuel brought to it; reindeer could feed on vegetation along the way. That did not make travel effortless—animals still needed care, and the sled’s load had to stay within what they could pull—but it reduced dependence on a separate supply of fuel reaching a remote route.
In effect, the postal service matched its transport to the conditions: snow favored a sled, and reindeer could provide both the pulling force and much of their own energy. The memorable part is how literal the “delivery truck that ate its own fuel” was: the means of moving the mail could also forage for what powered it.
