ABS 2022
Variation in maternal style does not predict post-weaning calf survival in bottlenose dolphins
Ellen Jacobs1, Taylor Evans1, Vivienne Foroughirad1, Quincy Gibson2, Caitlin Karniski1, Ewa Krzyszczyk3, Janet Mann1. 1Georgetown, Washington, DC, , United States; 2University of North Florida, Jacksonville, FL, United States; 3Bangor University, Bangor, , Wales

Maternal style, the repeatable individual variation in traits related to maternal care, is an important influence on the early life experiences of dependent young, especially in social species like dolphins with an average dependency period of 4 years. Based on 30+ years of research on Indo-Pacific bottlenose dolphins (Tursiops aduncus) in Shark Bay, Australia we investigate the impact of maternal style on post-weaning survival. Using focal follow data (n=352 follows) to extract behavioral information about maternal characteristics, we examine 17 mothers of 49 calves < 2 years old. Building on previous work showing that maternal identity has a significant impact on maternal characteristics consistent across multiple calves, we use PCA and k-means clustering to divide mothers into styles based on activity budget, proximity maintenance, and direct care (nursing access). We use a Cox mixed effects model to look at survival from ages 2-10 to evaluate whether calves raised by mothers with specific styles had higher post-weaning survival. We find no significant differences in survival between styles, suggesting that divergent maternal styles achieve similar fitness outcomes.