The Crystal People are loosely based off the silicoids from an Alan Dean Foster novel, and while they didn’t practice cannibalism they were ridiculously pragmatic and didn’t blink an eye at altering their organs with surgery if the situation necessitated it. In fact they pulled out and replaced the human protagonist’s eyes without his permission, giving him much better ones that he could use without sunglasses on their world; they did it all while he was sleeping and so skillfully he initially assumed they just put eye drops in or something. (They apologized afterwards; they thought they were being friendly!) So my Crystal People are similarly very pragmatic; they waste nothing if they’re in dire situations.