On the heels of the sudden death of a newborn bottlenose dolphin last year, Brookfield Zoo is now expecting two dolphin calves later this year.
Two adult female dolphins, Allison and Allie, are both pregnant, zoo officials announced Wednesday. Allison is due late this summer or early fall, while Allie is due later in the winter. A due date hasn’t been determined. Both dolphins are being closely monitored through blood tests and ultrasounds, and the fetuses look healthy and are developing normally, said Sathya Chinnadurai, Brookfield Zoo’s senior vice president for animal health, welfare and science.
Last year, Allie gave birth to a male dolphin, the zoo’s first birth in more than 10 years. But the 4-day-old calf died suddenly after a meconium aspiration, meaning he inhaled fluid into his lungs, zoo officials said.
Now that both Allie and Allison are expected to give birth around the same time, the habitat will further simulate a wild environment, according to Rita Stacey, the zoo’s senior vice president of programs and impact. Allison and Allie, like many pregnant and nursing dolphins, have been and will continue to spend more time together as they go through the gestation period together.
“We know that mothers that are pregnant at the same time tend to hang out together, and they actually form nursery groups when the little babies are born,” Stacey said. “So we’re really replicating nature here, and so we we are very excited to hopefully have a nursery in the very near future.”
The meconium aspiration of Allie’s calf last year couldn’t have been predicted and doesn’t mean Allie can’t deliver a healthy calf, Chinnadurai said. The mothers and calves will be monitored closely, including 24-hour observation for the first month after birth, but the zoo is still prepping for unexpected obstacles.
“Even when everything goes according to schedule, we still keep a close eye just to make sure there aren’t any unforeseen consequences,” he said.
As soon as they’re born, the calves’ care teams will begin looking for them to hit certain development milestones, the first of which will be swimming to the surface of the water for a breath of air. They likely will begin nursing around eight to 10 hours after birth and closely watch their mothers to model their other behavior.
The calves will be introduced when it’s determined they’ve both had enough time to bond with their mothers, and they’re expected to interact and socialize with each other as well as their mothers, fathers and other dolphins. It’s unclear which of Brookfield’s two male dolphins fathered the calves, but the zoo plans to conduct paternity tests after each is born.
Each calf’s sex also hasn’t been determined. The calves will live with their mothers at Brookfield for the first years of their lives, but males will be separated from their family and transferred to a partner of Brookfield to avoid inbreeding. As male dolphins age, they spend more time further away from their mother and other dolphins, and between the ages of 5 and 7, they’ll be ready to move.
Both Allison and Allie will need to get used to “feeding on the fly,” or nursing their calf while swimming. Allie has given birth and raised calves before, but for Allison, a first-time mom, this will be a new skill.
The dolphin building will be closed for up to a few weeks after each calf is born to allow the mother and infant to bond, and zoo staff will determine when it’s time to debut the calves to the public based on their development, Stacey said.