When discussing nedarim, how clear does a statement need to be in order for a person to become obligated in it? What if the statement that is made can be interpreted in more than one way?
Although our Mishna rules that stam nedarim le-hahmir – that we will be stringent with regard to the interpretation of vows – the Gemara quotes a Mishna that states sfeik nezirut le-hakel, seemingly indicating that regarding the laws of a nazir we will tend towards leniency. Since we have learned that nezirut is a type of neder, how are we to understand this contradiction?
Rabbi Zeira responds by presenting a baraita that shows a disagreement between tannaim in situations of doubt, and argues that our Mishna and the Mishna about the nazir have two different authors. What if a person sanctifies all of his domestic and wild animals – does this include a koy or not? The Tanna Kamma rules that it does (i.e. he interprets the statement to include unclear situations), but Rabbi Eliezer rules that it does not.
Identifying the koy is a difficult task. Even though it is mentioned many times in the Mishna and Talmudic literature, that is not because it is a common animal, rather because its status between a wild and domesticated animal allows it to be a test case for many halakhot. The disagreement as to its identification began in the time of the Mishna, when some of the Sages argued that it is the offspring of a deer or similar animal with a goat. Others claim that it is a unique type of animal – an Ayal HaBar.
The Ayal HaBar can be identified with the mouflon sheep, which, according to many, is the forerunner of domesticated sheep. It is distinguished by its short hair and grey color; a nimble climber, it lives in mountainous regions, today mainly in uninhabited areas in Europe. It is likely that the clear similarities between a koy and a sheep, together with its being a wild animal, led to the Sages’ confusion about its classification.
Its name – koy – and even the pronunciation of the name, are themselves the subject of disagreement.