Perhaps all the friendly (key word here) smiles captured here contain some sort of magnetic properties that encourage opposites to attract?
the leopard will lie down with the goat,
the calf and the lion and the yearling together;
and a little child will lead them.
"If anyone wants to be first, he must be the very last, and the servant of all."
36He took a little child and had him stand among them.
Taking him in his arms, he said to them,
37"Whoever welcomes one of these little children in my name welcomes me;
and whoever welcomes me does not welcome me but the one who sent me."