I have 4 dogs...a senior dachshund (10), an SPCA mixed terrier (4), and 2 yorkies that I got 6 months apart from each other, one is 25 months old, & the other 18 months old. The yorkies are super-bonded to each other. The dachshund still treats the yorkies like her "pups", but nothing compares to how the yorkies are with each other.
  http://www.yorkietalk.com/forums/gen...rkie-love.html