Zoological Studies

Vol. 57, 2018

(update: 2018.05.03; 06.07) 

The Development of Mother-Calf Interactions During the First Year in Yangtze Finless Porpoises (Neophocaena asiaeorientalis asiaeorientalis)

Ran Chen1,3, Wenbo Li2, Wenhua Jiang3, Bangyou Zheng3, and Jinhua Li1,4,*

1School of Life Science, Anhui Normal University, Wuhu, China
2School of Resources and Environmental Engineering, Anhui University, Hefei, China
3Tongling Freshwater Dolphins National Nature Reserve, Tongling, China
4School of Life Science, Hefei Normal University Hefei, China

(Received 21 January 2018; Accepted 19 April 2018; Communicated by Benny K.K. Chan)

Ran Chen, Wenbo Li, Wenhua Jiang, Bangyou Zheng, and Jinhua Li (2018) Mother-offspring interactions are widespread in humans and other mammals, and play an important role in offspring survival and development. Mother-calf interactions have been described in a wide range of ocean cetacean species, but they have not yet been documented in freshwater cetaceans. In this study, we observed the behavior of two mother-calf pairs of Yangtze finless porpoises living in Tongling Freshwater Porpoise National Natural Reserve, China, to explore the maternal relationship between mother porpoises and newborn calves during the calves’ first year. The results showed that mothers performed significantly more approach behaviors and fewer leave behaviors than calves during the lactation period, but performed significantly fewer approach and more leave behaviors than calves during the non-lactation period (starting from the seventh month after birth). The landmarks for maintaining intimate relationships within each mother-calf pair occurred within sixth months of birth. The duration of calf separations from their mothers increased with calf age.

Key words: Approach-leave behavior, Hinde Index, Mother-calf, Interactions, Yangtze finless porpoises.

*Correspondence: Ran Chen and Wenbo Li contributed equally to this work. E-mail: jhli@ahu.edu.cn