here are our 101 favorite dog breeds. (And yes, No. 101 could easily be No. 1... in your heart.) LONDON, ENGLAND - DECEMBER 20: Louise, an 8-year-old Border Terrier who has been at Battersea for ...

So, if you're curious about what makes these mini dogs tick, here are some standout traits according to Hills Pet and the American Kennel Club. You might also be interested in: Yorkshire Terrier ...