Few pure breeds with the longest life-span include Chihuahua, Dachshund, Pomeranian, Toy Poodle, Pug, Maltese, Miniature Schnauzer, Beagle, and Yorkshire terrier. Cavalier King Charles Spaniel Life Span Assuming there are no health issues, the Cavalier King Charles Spaniel has an average lifespan of about 9-14 years.