Bottlenose Dolphin Calf Social Development Over the First Two Years of Life

As dolphin calves develop, they are observed spending less time with their mothers and more time engaged in independent activities. In this study, the social development of nine dolphin calves (Tursiops truncatus) housed in naturalistic sea pens at the Navy Marine Mammal Program in San Diego, CA were studied over the first two years of life. Focal animal behavioral ethogram data were collected using a 30 second scan sampling technique over multiple 10-minute trials. The predominant swim positions and individual behaviors were observed. The results showed developmental patterns across every three months and between the individual dolphins, in which there was an increase in independent behaviors over time. For every three months, a significant increase was seen in solo swim position and a decrease was seen in infant and echelon positions. These findings are consistent with past research, which has found that there are significant differences in calf behavioral development in swim positions based on calf age. Variation was observed between individuals and may be due to the experience or type of mother, the unique personalities in the calves, or a combination of both