The broad outlines of basic animal motivation are easily stripped to bare bones: food deprivation motivates food seeking, sleep deprivation promotes sleep, sexual stimulation promotes reproductive behavior, and the prospect of imminent death by predation induces fear and anger which evoke defensive and offensive attack behaviors.
Of course, when these existential dominant drives are not on the psychic regulatory and operational front-lines, other subordinate drives, such as curiosity and orienting and re-orienting reflexes, i.e., the careful examination of objects of thought, may successfully compete for operational space.
Conversely, nothing obliterates subordinate drives such as curiosity and reasoned inquiry like the induction of primal homicidal mania.