Changes in Body Girth and Intermammary Distance During Pregnancy in a False Killer Whale (Pseudorca crassidens) in Managed Care

The aim of this study is to record the changes in body girth and length between mammary slits during pregnancy in a female false killer whale (Pseudorca crassidens) for the purposes of developing a breeding program in managed care. A female false killer whale at the Okinawa Churaumi Aquarium mated on 15 May 2020 and gave birth on 11 July 2021. Intermammary distance (MD) and body girth at the anterior (G1) and posterior (G2) insertion of the pectoral fin, anterior (G3) and posterior (G4) insertion of the dorsal fin, anterior part of genital slit (G5), and midpoint of the anus (G6) were measured at intervals ranging from two days to one month from July 2020 to December 2021. There were significant positive correlations between G1 to G6 and days to delivery, with correlation coefficients of 0.60, 0.75, 0.97, 0.97, 0.91, and 0.73, respectively. Correlation coefficients greater than 0.9 were observed for G3, G4, and G5. MD increased sharply from seven days before delivery. These findings suggest that selected body girth measurements, together with MD, may provide useful information on fetal growth, uterine condition, and impending parturition in false killer whales.