Brookfield, IL—The Chicago Zoological Society (CZS), which manages Brookfield Zoo, is happy to announce the birth of a male bottlenose dolphin calf. The approximately 35- to 40-pound, 3½-foot-long calf was born to first-time mom Allison, age 9, on December 12 around 1:15 p.m.

Following the birth, staff observed several key milestones. These included nursing and slipstreaming, which is when the calf is able to rest next to his mom Allison while she is on the move. A mother makes this hydrodynamic wake as she swims.

“We are encouraged with the behavior we are seeing from both Allison and the calf,” said Rita Stacey, curator of marine mammals for the Chicago Zoological Society. “However, we remain cautiously optimistic as the first 30 days are extremely critical in the calf’s life.”

Allison and her calf are currently in the Seven Seas main habitat along with experienced mom Tapeko, 33; Merlin, Tapeko’s 1-year-old son; and Magic, Merlin’s 1-year-old half-brother. “The current grouping mimics what occurs in the wild,” continued Stacey. “Dolphins are gregarious and form fluid social groupings throughout their lives. Mothers often form groups with other females who help in raising their young. Having successfully raised several calves of her own, including Merlin, Tapeko is a wonderful role model to Allison.”

As with many other mammals, infancy is a delicate time for bottlenose dolphins. A dolphin birth is not considered successful until the calf reaches about one year old. According to Dr. Randy Wells, who is a leader in the field of wild dolphin research and director of the Society’s 45-year Sarasota Dolphin Research Program (SDRP), the first year of life is the period when most dolphin calves are lost in the wild.

Through the work of CZS’s dedicated staff, the relationships among Allison and the other dolphins and the marine mammal care team are built on trust. Because of this bond, the dolphins voluntarily participate in their own health care by allowing animal care staff to conduct thorough physical exams that include getting weights, taking blood samples, and performing other health assessments very similar to the care people receive from their doctors.

“The prenatal care Allison received during her pregnancy allowed the Society’s animal care and veterinary staff to monitor her health, as well as that of her developing calf,” said Jennifer Langan, DVM, Dipl. ACZM, associate veterinarian for CZS. “By monitoring fetal development through routine ultrasound exams, we were able to evaluate the growth rate, size, and sex of the calf and determine due dates to prepare for the impending birth.”

The exhibit’s underwater viewing area will remain closed until further notice, and all dolphin care and enrichment Zoo Chats have been temporarily suspended to allow Allison and her calf time to bond. For updates, the public can visit