Can you explain why the word species always has a plural form? If I wanted to say 'Cows is a very well known specie for providing us with the most delicious milk in the whole universe'. Once I'd written it, my auto checker suggested adding an 's' to the world 'specie', even though cows is only one type of beasts. I've looked up on some other website that it's a convention between scientists to use the plural form, but it didn't answer my question.