These dogs have one of the longest ‘puppyhoods’ of all dog breeds: boxer dogs are only considered to be fully mature when they reach the age of three years. (11/15) by Judy Powell August 25, 2020, 3:09 pm Credit Judy Powell 0 Previous 11/15 Next View full list See more Previous article They like to travel with you. Next article The Labrador Retriever is actually originally from Newfoundland, Canada. They were originally called the dogs of St. John. Leave a Reply Cancel replyYour email address will not be published. Required fields are marked *Comment * Name * Email * Website Save my name, email, and website in this browser for the next time I comment.