Harry Potter's spirit animal is a dog.
Harry Potter is selfless, kind, and brave, so his spirit animal is a dog. Dogs are pack animals who work together; they cannot be selfish if the pack is to thrive. Several times throughout the story, Harry puts his life on the line for his "pack," risking his life to protect the other students at Hogwarts. Dogs are kind, affectionate, domesticated animals who can be used in therapy and human aid. Harry is kind to even the lowliest of characters, like Dobby, the house elf. There have been several cases of dogs risking their lives to save their owners, diving in to freezing water, or running into burning buildings. Harry shows bravery constantly by risking his life for the greater good.
Draco Malfoy's spirit animal is a cat.
Draco Malfoy is selfish, mean, and cowardly, so his spirit animal is a cat. Cats are solitary animals who only give attention to people when they need something. Draco, in much the same way, uses people for what he needs and doesn't have any deep meaningful friendships. Cats are not known for being very loving, and can be quite ill-tempered. Draco is rude and acts superior to everyone because he believes his bloodline is pure. Cats, when confronted with the unknown or something they dislike, hide or run from it. There are several examples of Draco's cowardice throughout the story, and lets others take the fall for him or stand between him and danger.