California Code, Civil Code - CIV § 1815

(a) By the accidental leaving or placing of personal property in the possession of any person, without negligence on the part of its owner.

(b) In cases of fire, shipwreck, inundation, insurrection, riot, or like extraordinary emergencies, by the owner of personal property committing it, out of necessity, to the care of any person.

(c) By the delivery to, or picking up by, and the holding of, a stray live animal by any person or public or private entity.

(d) By the abandonment or leaving of a live animal, as proscribed by Section 597.1 of the Penal Code, in or about any premises or real property that has been vacated upon, or immediately preceding, the termination of a lease or other rental agreement or foreclosure of the property.