This image is a slightly modified (bigger ears and darker tail) version of one which comes from the Art Today commercial clipart website, and is © 2000-present www.arttoday.com.
Art Today lists the source as GraphicCorp 11 - Animals (presumably a directory on a clipart CD), published by Hemera Technologies. The artist is not given.
This image can also be found on CDs produced by the clipart publishing studio greenstreet Software, and as such may be copied for non-commercial purposes.