Do you know how we can turn a singular noun into a plural noun? The solution is simple. Just add an '-s' at the end of the word, and whoosh, the job is done. The word 'house' becomes 'houses', 'word' ...

Could it be that these are animals that were hunted, fished, or herded and that there was a convention that used the singular as a sort of generic plural when going after these creatures for sport or ...