Seventies movie about a newly discovered docile primate like species. A corrupt developer exploits them, using them as laborers and paying them in shell barrows filled with cans of Spam. The film end with a courtroom scene where a researcher is trying to prove the intelligence of the primates, it becomes agitated, climbs a bookcase that falls over and crushes it to death.
Except for the ending, it sounds like Jerry is a Man from Masters of Science Fiction, but that is from 2007.
https://www.imdb.com/title/tt0066384/?ref_=tt_urv