Instinct — innate behaviors or natural impulses not based on reason; the inborn tendencies of humans or animals.
母親の本能で赤ちゃんの異変に気づいた。
By maternal instinct, she noticed something was wrong with the baby.
動物は危険を感じると本能的に逃げる。
Animals instinctively flee when they sense danger.
生存本能が働き、必死に助けを求めた。
His survival instinct kicked in and he desperately called for help.