I find it amusing that this is driven by the particular visualisations of the characters. I.e. if it were a chicken and a rabbit would you have also made this assumption?
For me it's a variant of a classical "move a wolf, goat and cabbage across the river", where you can't have some of them on the boat together, because it would be eaten.
A fun Easter egg would be to have the dog eat the rabbit if both of them are on the boat node.
I didn't even realize two animals could be on the same node at all until I needed to get both rabbits to the carrot.
If it was a chicken and rabbit I think I would have tried to overlap them