Little has been written about the growth and development of the Pacific white-sided dolphin, Lagenorhynchus obliquidens. To our knowledge, Sea World of Texas has the only captive born Pacific white-sided dolphin to survive beyond a year of age. This animal has provided information concerning length of gestation, development during utero, length of labor, time from birth to passage of the placenta, time from birth until observed nursing, nursing times, consumption of solid food, and growth in length and weight.

Gestation appears to be approximately twelve months. Growth in utero, as viewed with ultrasound, approximated the Tursiops fetal growth curve (Williamson et. al.) closely enough to extrapolate weeks prior to birth with reasonable accuracy in this calf. Table 1 provides information on parturition and calf size. Figure 1 illustrates nursing times while Figure 2 shows the daily average respiration rates per 5 minutes for the calf and mother for the first 21 days after birth.

The mother was alone in the pool when she gave birth to a female calf on September 5, 1993. The first introduction of another animal occurred at 91 days after birth. The calf would separate from the mother in the same pool at 52 days. Separations in separate pools first occurred at 68 days. Playing with fish was observed at 72 days and the first fish noted to be eaten by the calf was at 128 days after birth. Figure 3 illustrates food consumption from day 128 (first observed to eat a fish) through January 1995, day 518. The initial weight for this animal was assumed to be the average of two other calves with known weights between birth and two days of age. Figure 4 compares weight and length to age.

All calves were delivered flukes first, i.e., longitudinal, posterior presentation in a dorso-sacral position.

From the limited data available on Pacific white-sided dolphin calves, it appears that the birth weight is between 12 and 14 kilograms, the birth length is very near 91 centimeters, and adult size is reached within two years. Based on data collected at Sea World, adult weight is 131 kg to 161 kg and adult length ranges from 2.08 meters to 2.2G meters.

Figure 1. Total Observed Nursing per 24 Hour Period

Figure 2. Daily Average Respiration rate per 5 minutes for Mother and Calf

Figure 3. Food Consumption from Day 125 when the Calf was First noted to eat fish through day 518

Figure 4. Compares Weight and Length to Age