Self-preservation

Self-preservation is a behavior or set of behaviors that ensures the survival of an organism. It is thought to be universal among all living organisms.

Self-preservation is essentially the process of an organism preventing itself from being harmed or killed and is considered a basic instinct in most organisms. Most call it a "survival instinct". Self-preservation is thought to be tied to an organism's reproductive fitness and can be more or less present according to perceived reproduction potential. If perceived reproductive potential is low enough, self-destructive behavior (i.e., the opposite) is not uncommon in social species. Self-preservation is also thought by some to be the basis of rational and logical thought and behavior.

The opposite of self-preservation is self-destructive behavior.