Riding

The Mishna had stated: If two people were riding on an animal, or one was riding and one was leading the animal, and each of them claims that he owns the animal, each should swear that they do not own less than half of the animal, and they should then split the animal.

Rav Yosef said: Rav Yehudah told me: I have heard from the Master Shmuel two rulings regarding a rider and a leader. One of them does acquire the animal, and one does not. However, I do not know which of them acquires and which does not.

It is evident from the Gemora that the “leader” is acquiring the animal with an act of meshichah (pulling it).

Many Rishonim understand the kinyan by the “rider” as follows: The animal is walking due to the weight of the person sitting upon it. This is tantamount to “pulling it.”

Tosfos explains: The rider is holding onto the animal’s reins and it is moving a little because of him.

Rashi seems to say that the “rider” can acquire the animal even if it doesn’t move at all. It would seem that “riding” would be a new type of kinyan.

The Reshash cites the Ritzvash that the “rider” acquires it because he is “using” the animal. This would be similar to a propriety act done with land.