What is it called when behavior is not learned?

The term "innate" accurately describes behavior that is not learned but rather instinctual or inherent. Innate behaviors are those that animals are born with and do not require any previous experience or training to perform. These can include reflexes, survival instincts, and other automatic responses to stimuli in the environment. For example, a puppy may instinctively know how to suckle or a bird may have an instinct to build a nest without ever having seen another bird do it.

The other options do not pertain to the concept of learned versus unlearned behavior. Descriptors like "interesting," "incredible," and "internal" do not convey the specific meaning of behavior that is naturally occurring without the need for experiential learning. Thus, "innate" stands out as the appropriate term for this concept in behavioral studies.