No, he's not really learning to share. That would be ludicrous. He's only 13 months (and a day) old.
But he is sharing his apple with his kitty. That's pretty cute.

And he's buttering up Tom so that Tom will want to share his fries with Sebbie.

Marc was allowed to chew on one of Sebbie's blocks. Very generous of Sebbie. He usually likes to slobber on all his toys himself, but maybe the droolers have a certain kinship.

Mmmm. They're so cute.