Other mistake: When Bambi is walking out with his mom for the first time we see, he meets the quails and that is followed by the possums. The possums are hanging upside down. When the possums are shown hanging upside down, the mother possum is on the right-hand side of the babies. When it shows them from Bambi's perspective after he turns his head upside down, she is on their right side. This may have been an intentional decision since maintaining the correct orientation might be perceived as more jarring. (00:09:12)
Other mistake: After the great fire scene there is a raccoon that drags her baby to shore and begins cleaning it. A few seconds later the baby has jumped across to the other side of his father and siblings, but the mother does not stop licking. This error has since been fixed in newer releases.
Answer: Probably so he would not think he is superior to the other fawns and try to lord over them. She would have told him about his father when he was older. This is also a literary plot device by setting up a dramatic reveal at a crucial time (right after Bambi's mother is killed) that Bambi learns his father is the Great Prince. This has a greater emotional punch.
raywest ★