Nocturnal activity patterns and mother-offspring interactions during early rearing in yellow-backed duikers (Cephalophus silvicultor)

Abstract In view of the increasing loss of biodiversity, the establishment of ex-situ populations is a valuable approach for the conservation of endangered species. The expertise of zoos, coupled with their extensive network of institutional connections, positions them as a unique entity in the effort to maintain ex-situ breeding groups and thereby contributes to the mitigation of the global biodiversity crisis. However, with only approximately 500 EEPs (EAZA Ex-situ Programs) and over 42,000 species classified as threatened, it is crucial to expand these programs. Moreover, to ensure a high standard of animal welfare, it is important to understand species-specific and individual needs. Keeping yellow-backed duikers ( Cephalophus silvicultor ) in zoos has proven difficult due to high infant mortality. In this case study, we examine two juveniles and their mother within a zoological environment to better understand the critical phase of rearing offspring, thereby improving survival rate and welfare in zoos. A behavioral study was conducted on the nocturnal behavior, analyzing the first 10 nights after birth of two calves by assessing video footage. The findings fit well with knowledge of the nocturnal behavior of other ungulates and age-related differences, with lying being the predominant behavior at night and juvenile animals spending even more time in this body pose. Interactions between mother and offspring are characterized by numerous suckling attempts by the calves and up to 35 min of total suckling time in one night. In addition, yellow-backed duikers in zoos exhibit natural behaviors, such as placing their offspring in a nest and displaying minimal interaction with each other, with the exception of nursing.