Vocal repertoire of the critically endangered whiteheaded langur(Trachypithecus leucocephalus): Call types, acoustic structures, and related social-ecological contexts

DEAR EDITOR,We examined the vocal repertoire of the critically endangered white-headed langur(Trachypithecus leucocephalus)inhabiting karst limestone forests in China.We identified 17 call types across all age/sex classes based on human auditory perception,spectrogram assessment,and quantitative analysis of 25 acoustic parameters extracted from 409 high-quality calls.In total,11 types of calls produced by adults corresponded to the simple one-male multi-female social groups of white-headed langurs.