niltrias wrote:However, many non-domesticated animals in English (excluding most but not all birds, oddly enough) can be referred to by a plural unchanged from the singular form. Some domesticated animals, such as sheep, also fit this pattern.
I'd argue that is for different reasons, though. Nouns such as "deer", "fish" and "sheep" simply have a plural form that is the same as the singular form as a modern remain of Anglo-Saxon plural formation from before the Norman invasion (and I love them). In that regard, they are the same as "ox"--"oxen", but simply of another declension. "Bison" seems to have a similar plural form, but I cannot really tell -- it is nor a word I encounter daily. :)
With regards to your example of "where the buffalo roam", I would interpret "roam" not as the plural conjugation of the indicative form of the word, but as the present subjunctive (possibly purely as a wishful description of the area of the home, or possibly for temporal agreement with the first clause if "give" could be interpreted as being present subjunctive, too -- I admit I'm not sure which is the most reasonable interpretation, though I'd guess the former). The "buffalo", on the other hand, truly is the singular form, and I guess the poem is, simply, from the time when the subjunctive was still in active use, and when the singular form of nouns was regularly used for generalizing the concept (as seen in such constructions as "man is good by his nature" when referring to "all men"; or the famous "der ewige Jude"). A very beautiful construction indeed -- I can tell it is from a time when man still knew how to write. :)
I've never seen "bear" or "boar" in a plural form other than "bears" or "boars", though.
Conclusion: I see no reason to accept any plural form other than "aurochsen". ;)