Behaviour 2019
Individual Differences in Socio-sexual and Agonistic S-postures of Belugas (Delphinapterus leucas)  
Malin K. Lilley1, Jackson R. Ham2, Devin Forey-Vargas 1, Amanda Lozano1, Vivian Paredes1, Malin R. Miller3, Heather M. Manitzas Hill4. 1Texas A & M University- San Antonio, San Antonio, TX, United States; 2University of Lethbridge, Lethbridge, Alberta, Canada; 3SeaWorld San Antonio, San Antonio, TX, United States; 4St. Mary's University, San Antonio, TX, United States

Previous research identified cetacean “s-postures” as agonistic body postures. However, recent research on belugas (Delphinapterus leucas) reported a distinctive s-posture as part of socio-sexual behavior. We documented individual differences in s-postures for 20 belugas housed at SeaWorld San Antonio from 2007 to 2019. S-postures events were examined to document the exact body position and what other behaviors occurred before, during, and after the s-posture. Overall, socio-sexual s-postures, where genitals and head are directed towards the recipient, were accompanied by lateral presentations, pelvic thrusts, genital rubs, and erections. Although less frequent and shorter in duration, agonistic s-postures, where the genital region is withdrawn, were typically accompanied by head jerks, open mouths, and bubbles. Individual differences in the use of s-postures and accompanying behaviors reveal further patterns in how these postures may play a role in beluga social behavior. Historically, s-postures have been described as aggressive, which may not be accurate for all species. Thus, future cetacean research should specify which s-posture is displayed and in what behavioral context.