Dougal ranks #3378 with 24 registered male pets, appearing almost exclusively on dogs. It's a Scottish Gaelic name with medieval roots that has maintained a stubborn presence in British and Irish pet naming long after it fell out of use for humans — carried largely by one very specific television character.
The Gaelic etymology
Dougal (also spelled Dugald or Dùghall) derives from the Old Gaelic "Dubhghall" — "dubh" meaning dark and "gall" meaning stranger or foreigner. In medieval Scotland and Ireland it was often used to describe the dark-haired Norse invaders (as opposed to the fair-haired Danes, who were "Fingall"). It was a common given name through the medieval period and has survived into the present largely in Scotland and among Scots diaspora communities.
The Magic Roundabout factor
The Magic Roundabout, the beloved British children's television series that ran from the 1960s through multiple revivals, featured Dougal — a shaggy, somewhat grumpy dog with strong opinions about sugar lumps. The character became one of the most recognizable animated dogs in British television history. Naming a dog Dougal in the UK is almost always a reference to this character, even when owners claim otherwise. The name is so thoroughly associated with the show that it functions as a cultural marker of a specific kind of British childhood nostalgia.
Who picks Dougal
Predominantly British or Scottish pet owners, or Americans with strong Scots heritage. It works naturally on shaggy, long-haired breeds — Old English Sheepdogs, Bearded Collies, any dog that vaguely resembles the animated original. The name has a grumpy dignity to it that suits older dogs particularly well. Related Scottish dog names include Angus and Hamish.