Why is it significant that Bruno and Schmuel find out that they share the same birthday in The Boy in the Striped Pajamas?How does the shared...

To a great extent, the astonishment shared about both
boys' birthday is also reflective of the fact that each one has found another.  Shmuel
has retreated to this particular place along the side of the fence because he seeks to
be away from the intense pain that exists among "the pajama people."  Bruno is
astonished that he has found someone of his own age, a reminder of how life was in
Berlin before the family moved to "Out- With."  Both find one another in a setting where
companionship for both is extremely difficult.  The fact that they share the same
birthday almost creates the belief that their friendship was destined to happen, in a
sense.  From a symbolic point of view, the sharing of their same birthday also makes
each recognize how similar they are and that the only real difference between them is
the presence of the fence.  The fact that each lives on another side of the fence is the
only real difference between them, a compelling argument about how random selection and
pure chance played such a large role in determining life and death in the
Holocaust.