This page contains information regarding Star Trek: Lower Decks, and thus may contain spoilers.
Physiology and culture
According to Federation astral anthropology research, these "huge, furry creatures", were similar, but much larger than the anthropoids discovered on Hansen's Planet, and stood ten to twelve feet in height. They were described as appearing "like a giant ape".
They had not yet attained a traditional tribal culture, and existed in little more than loose associations. They employed a stone-age level of technology, wielding such weapons as leather shields, spears made with heads resembling Folsom points, and rocks. (TOS: "The Galileo Seven")
Thanks to the ingenuity of Montgomery Scott, Spock was able to get the shuttle airborne and escaped from the creatures with the remainder of the crew. This, however, was not before one of the USS Enterprise's landing parties, Landing Party 2 led by Lieutenant Kelowitz, encountered these anthropoids on the planet. During the landing parties encounter, they received two casualties: Ensign O'Neill was killed by a spear and Lieutenant Immamura got a dislocated shoulder and severe lacerations. (TOS: "The Galileo Seven")
The anthropoid shown attacking the Galileo crew was played by Buck Maffei, who stood seven feet tall and weighed 400 pounds.
In the stage directions from the script of "The Galileo Seven", this anthropoid was initially described as "a huge figure." Later in the script, it was characterized as "something very dark, very large, vaguely manlike [....] It looms enormously, [...] a large, black bulk." The anthropoid was also scripted to have shoulders, "large hairy arms," and footprints that were "Human in form, but impossibly large." A later description of a close-up view of the anthropoid's face referred to "beetling hairy brows, eyes, portions of the face of a gigantic ape-like creature."
In a memo Robert Justman sent to Gene Roddenberry (on 23 August 1966), Justman commented about these creatures, "Naturally, we can't afford to ever really show the denizens of this planet, but the continued references to them by our crew members who have seen them is certainly going to make the audience feel it is being cheated by not seeing them. If our crew members never see them, or at least seldom see them, I feel our story and our budget would be better served."
NBC Censor Jean Messerschmidt was also concerned about how the anthropoid would be shown. In a memo (dated 14 September 1966), Messerschmidt included a recommendation that pertained to the creature, whenever it was to appear in the episode, stating, "Please show restraint so it is not unnecessarily alarming or gruesome."