Siblings can be our longest lasting and most meaningful relationships in life, animal siblings being no different. This duo are each others best friends, besides their loving people. I have always felt that having two dogs in the same home is so beneficial for the pooches happiness. They keep each other company when us humans are at work, they are each others play buddies when it's time to have fun, they are partners-in-crime (the only downside is the mischief they get into together). With Cassidy and Sundance two is definitely better than one!