Cousins or Sisters?

So these are my girls! When I first moved to LA, I lived with my brother in Santa Monica and we together had Kate. My brother found her so all and all I guess she was his but we lived together for three years and she was our dog! I will never forget the evening I dropped Kate off at my brothers new house I felt like I was abandoning my child. It was horrible, I cried hysterically for hrs (I seriously am not kidding! Ask Lawrence) Mind you he only moved like 4 miles away and I could pick her up whenever I wanted, but it was one of the most traumatic experiences I ever had - LOL! So we shared her for a awhile and it worked out ok but it still wasn't the same as having your own dog. I would come home from work and ask Lawrence if he wanted to go for a walk....He would always answer "Babe, I'm not your dog! - I don't need to be walked!" but one night he followed this by saying " I think its time you get a new dog of your own!! " I was ecstatic! Looking for the new right dog sort of became an obsession and I fell in love with a different dog everytime I went to the kennel and every dog I wanted Lawrence had some reason why it was not the "one" - he would say.... too big, not big enough, to hyper, ugly, too hyper.  I started think he would never say yes to any dog and then I found Lucy! I was on the way to the grocery store and I was at a stop light when I spotted the cutest black and white dog at a pet adoption event going on at a local pet store. I pulled over and went to go meet her and she immediately rested her head in my hand and put all of her weight on my hand like she was so exhausted she just needed me to hold her head up. It was so adorable, I immediately called Lawrence and he came to meet her and to my surprise he said almost immediately "She's the one" 

Anyways, so now these two ladies hang out regularly and are best friends! 

But what does this make them cousins or step sisters?