Sudras

Sudra means almost animal life — no cleanliness, no hygienic principle,
simply working for living. No other ambition, no spiritual education, but
some way or other filling our life. Just like animals, they become dependent
on somebody. Whatever he likes, he can do on that animal. Sudra is not so
dependent, but actually they are dependent. Just like in your country the
Negroes were slaves, but fortunately they have been made free. Actually they
were being treated just like animals. So sudra life means completely
dependent on the other three higher class.
Srila Prabhupada lecture, March 12, 1969