Perception of absolute pitch (AP) has often been regarded as a qualitatively distinct ability, yet recent work has demonstrated that perceivers unable to label absolute pitchesthe hallmark of true AP perceptionstill possess some knowledge of absolute pitch level. This is sometimes termed implicit AP. What distinguishes the two types of AP? In two experiments using a melody-learning paradigm and eye tracking, we explore the pervasiveness and automaticity of implicit AP. We argue here that implicit AP reflects a phylogenetically older encoding of pitch information shared with other species, while true AP primarily reflects perception of pitch chroma, which may be unique to humans.