Clark is a fox released for the Santa Barbara Zoo together with his brother Lewis, and the two are identical except for their eyes. Clark's are green and Lewis's are blue.
Clark's own tags work against him. The left inside of his swing tag introduces Lewis by name rather than Clark, alongside the zoo's note that the full purchase price goes to support it. The example examined for the source also had Clark's name misspelled on the tush tag. So a Clark whose swing tag names the wrong fox is normal for this release, and the eye colour is what settles which brother you have.
