Since Darwin, emotion and survival have been intertwined. He proposed that emotional states of mind (feelings like fear or pleasure) help organisms adapt and survive. This equation of emotions (feelings) with survival has guided the field ever since. It is now common to use so-called emotional responses as a way of assessing whether a human or animal is in a particular emotional state of mind, like fear. But there is actually little evidence that feelings like fear are hard-wired in the brain and inherited from our mammalian ancestors. What we have inherited, instead, are circuits that detect and respond to threats in preprogrammed ways. Threat detection sets off a cascade of responses in the body and within the brain that serve as physiological ingredients that, when evaluated in light of the physical and social environment and memories about personal experiences or facts, then compel us to feel afraid. Other survival circuits are involved in managing energy, fluid balance, thermoregulation, and reproduction. Survival circuits are conserved in mammals and to a large extent across vertebrates. Although invertebrates have different nervous systems and thus different circuits than vertebrates, they nevertheless have their own circuits for managing fundamental tasks necessary for life. Indeed, even unicellular organisms have to solve similar life tasks. We should be asking which circuits and functions present in other animals are also present in humans, not whether fear or other human emotions are present in other mammals.