Study Guide Bava Kamma 40 Today's daf is sponsored by Judy Shapiro and Shira Krebs in memory of Ari Yehiel Zenilman, Ari Yechiel ben Avraham Reuven v'Miriam HY"D, who fell in battle yesterday. May his family know no more sorrow.  Rava and Abaye each gave different explanations for Rabbi Yaakov's opinion regarding an animal owned by one who is deaf, not mentally capable, or a minor - the guardian pays half damages. Why did Rava not choose a more simple straightforward explanation? A guardian can be obligated to pay the full payment but does not pay ransom payment in the event the animal kills a person. This is because a minor is not obligated in this payment as it is for atonement purposes and not for compensation. Is the nature of the ransom payment a tannaitic debate? Some other questions regarding the nature of the ransom payment are raised by Rabbi Acha bar Yaakov and he stumps Rav Nachman on them. His questions were: Can joint owners share it and if so, how? Can we assume one would take it as seriously as one who is obligated a sin or guilt offering? Two issues are raised in a braita about an animal who is borrowed - one where the borrower thinks he is a shor tam but he was a shor muad - the law is that they share the full payment (each pays half). If the ox became a shor muad while he was borrowed but when he is returned to the original owner, he reverts to being a shor tam.  What is the reasoning behind these laws and how can a seeming contradiction between the two be resolved? Can an animal used for bullfights who kills a person be used for a sacrifice?