Again, I think if you can get it, PAO is the simplest, safest way to do it.
Same kingdom (animal, vegetable, mineral) +5 (animal to animal, check)
Same class (mammals, fungi, metals, etc.) +2 (mammal to mammal, check)
Same size +2 (nope)
Related (twig is to tree, wolf fur is to wolf, etc.) +2...