when kids are young and still in the throes of innocence, they do not know to define color or status and they play and love each other. Before they are taught differently, they do not do anything but accept. They just know love until life or situations change them. I have noticed recently the same with kittens. Although the situation is different as when cats get older it is just normal to get territorial, as kittens they are accepting. I recently had two mom cats dumped off. They had their kittens on different sides of the house and for the first eight weeks, they never even saw each other. Then, the last couple of days, they have found each other. They do not understand yet that they are different. They play together, they do shoo the others off. I just found that fascinating. And beautiful.