Hermione’s Patronus is an otter, J.K. Rowling’s favorite animal. Otters are known for their playfulness and intelligence. The otter also is in the same family as the weasel, which is the origin of the surname Weasley
Ron’s Patronus is a Jack Russel Terrier, which J.K. Rowling has said to have as a pet. Jack Russel Terriers are known for their loyalty and protectiveness, and have a lively, energetic, and almost hyperactive personality. They are also particularly noted for chasing otters in deep water.