The Picts were picked by the same people who killed the kilts. In ancient times, kilts were not made of wool, as they are today, they were made of animal hides. To make anything from an animal hide one first had to find where the animal was hiding. More often than not the animal would be found hiding beneath a really nice looking fur coat. At first, people tried to hide under the fur coats with the live animals, often with disastrous results. Fortunately, the DNA of those people is no longer part of the gene pool. More intelligent people were able to figure out that it was easier for them to hide under the fur coat if they first dispatched the animal that was previously hiding there.

It's hypothesized that the first conversation in which the word "kilt" was used went something like:

"Org! How you today hide where Bear hide yesterday?"

"Well, Dorg, being a much more highly evolved example of Homo Sapiens than you and your ilk, I killed the bear and took his hide."

And Dorg, not being the brightest cinder in the campfire, began to refer to Org's new apparel as a "Bear hide kilt".