Fruitcake Theory (Unabridged‪)‬

It's Christmas and one of the aliens wants to go shopping at the mall to get in the proper holiday spirit. The trouble is, he doesn't know an elf from an elephant. Here's a wacky Yule story about intelligence, diversity, and too many tins of fruitcake.
Author James Patrick Kelly is a two-time winner of the Hugo Award and a 2007 Nebula Award winner. His stories appear frequently in Asimov's Science Fiction, and he writes the magazine's "On the Net" column. Publishers Weekly has called him "a meticulous craftsman in the demanding short-story form".