Correlation between blow progesterone and behaviour in pregnancy and lactation in Tursiops truncatus

CORRELATION BETWEEN BLOW PROGESTERONE AND BEHAVIOUR IN PREGNANCY AND LACTATION IN TURSIOPS TRUNCATUS This study overlaps hormonal and ethological data assessing dynamics and correlations between progesterone levels and behavioural displays. A female bottlenose dolphin was systematically monitored at Rimini Delfinario (Italy) from July 2006 for 52 consecutive weeks throughout the gestation and for 14 weeks after delivery. A new procedure based on daily blow progesterone sampling was applied with hormone concentrations determined by RIA. At the same time, focal observations of behaviour were carried out twice a week for a total of 458 hours. The results of blow sampling showed mean values of progesterone significantly different (p<0.01) between pregnancy (mean value 206.22 ± 13.71 pg/ml, range 86,48 – 503.46 pg/ml) and lactation period (mean value 33.61 ± 23.05 pg/ml, range 3.98 – 77.66 pg/ml). Pearson’s Correlation Test revealed that during the pregnancy progesterone was negatively associated to both locomotory and social activities, such as fast swimming, being touched on the side or actively rubbing the venter on conspecifics. After the calf birth, a negative correlation appeared with behaviours like random swimming, jerking, pool rubbing and side slapping. The results show how progesterone levels directly reverberated in behaviour. On the one hand it appeared quieter and less requiring interaction during the pregnancy. On the other, it became less restful and harmonic. In conclusion, the blow sampling integrated with behavioural observations guarantees stressless contexts for animals and unbiased data collection while the disclosure of correlated elements allows a multidisciplinary exploration of reproductive processes, animating and enhancing their comprehension.