The Great Dane is a German breed of large mastiff-sighthound, which descends from hunting dogs of the Middle Ages used to hunt bears, wild boar, and deer. They were also used as guardian dogs of German nobility. It is one of the two largest dog breeds in the world, along with the Irish Wolfhound. Great Danes have naturally floppy, triangular ears. In the past, when Great Danes were commonly used to hunt boars, cropping of the ears was performed to make injuries to the dogs' ears less likely during hunts.

Source: Wikipedia