Developed in late-1800s Germany from the now-extinct Bullenbeisser, the Boxer was originally a hunter and butcher's dog before becoming a beloved family companion. Athletic, muscular, and famously slow to mature, they retain their playful puppy personality for years. Loyal, patient with children, and protective without being aggressive — but the breed is prone to cancer (especially lymphoma and mast cell tumors), giving an average lifespan of only 10–12 years.
