The second part of the credits, in which, after wild animals and fights as were expected, you can see Tarzan's family, and particularly Jane and Kala looking moved.
The freeing of the Leopard men from La's slavery/control in "The Leopard Men Rebellion" was surprisingly heartwarming when one gets over the initial shock of the episodes twist ending.
After Edgar Rice Burroughs himself has been hearing about all of Tarzan's amazing exploits, Jane comes to say that all those stunts are only one part of the man. In truth, he's a much kinder and gentler person that his power would have him appear. Coupled with flashbacks of their romance.
All this gave Ed the inspiration he's been searching for.
"Tarzan and the Lost Cub" ends with the aforementioned leopard cub returned to his mother, both pay Tarzan and Jane a friendly visit later.
Before that, when the cub reunites with it's mother. It walks into a cave and sees her sitting curled up in the back looking sullen. Then she sees her cub, and smiles.