This movie was in theaters in the early 1970s. I don't remember much of the plot since I was about 12. People go into the jungle in search of something. They find an unknown humanoid species and they start studying them. The creatures had fur on their bodies. Their eyes were humanoid looking. They are loving creatures. I seem too remember one of them was pregnant and one of the men in the group was the father. There was dissent in the group as to whether these creatures are, or if they should be, classified as human. Near the end, one of the dissenters kills and cooks one of the creatures over a campfire and feeds it to the group as monkey meat...Or some such thing.
Possibly the 1970 film Skullduggery, based on a novel by "Vercors" variously titled but in English generally called You Shall Know Them. I haven't seen the movie nor read the novel, but from my memory of having read reviews of both in the past it sounds like a possibility. Someone who has seen the movie can perhaps elaborate.
On an expedition in Papua New Guinea, Tropis, a tribe of apelike creatures, are being used as slaves by humans. When one of the Tropis is allegedly murdered, the following murder trial centers round the question: are the Tropis a form of human or animal?