Since Osamu Shimomura discovered Green Fluorescent Protein (GFP) in jellyfish back in the 1960s (his work earned him the 2008 Nobel Prize in chemistry along with Martin Chalfie and Roger Tsien), the science of biology has never been the same. Since then, this incredibly useful tool (I even used it in my dissertation way back when) has found its way to transgenic pigs, dogs, and even cats.
NatGeo News has a nifty photo gallery of the various "glowing" animals - some of which crossed the line from science into commerce (the fluorescent GloFish). This one above is the GFP Rhesus Macaque Monkey, used to study Huntington's disease by researchers at the Yerkes National Primate Research Center in Atlanta.
Link - Thanks Marilyn!