Fin-back whales, as opposed to other whales, sink when killed, then float back to the surface one to three days later and are often located far from where they were killed. The custom of the Cape Cod area at the time of this case was such that a person who finds the body of a fin-back whale sends word to Provincetown, and the whaler sends someone to the whale to remove the blubber. A small fee is granted to the finder of the whale. Ghen (plaintiff) killed a fin-back whale for commercial purposes. Several days later, Ellis found the whale and, contrary to custom, sold it at auction to Rich (defendant), who harvested the blubber and oil from the whale carcass. Ghen sued Rich seeking to recover the value of the whale.