My Dog Meets His Long Lost Brother! Can Dogs Tell They're Related??

Ok ok, he's not long lost he just hasn't seen him since 8 weeks old! You can tell the two apart if you have a keen eye but they are so identical! They were stuck to each other's side while playing and so happy to see each other. Do you think they know they are related or dogs can tell it's their sibling, father, mother?? Let us know your thoughts below, I'm intrigued to see what the majority is.... x