‘Deeply saddened’: 4-day-old bottlenose dolphin calf at Brookfield Zoo abruptly dies

BROOKFIELD, Ill. (WGN) — A bottlenose dolphin calf born at the Brookfield Zoo last week has abruptly died, officials confirmed Thursday.

According to zoo officials, the male calf was born early Saturday morning and appeared healthy, but died abruptly on Wednesday evening.

“We know our guests and supporters share this sadness with us,” Dr. Rita Stacey, Brookfield Zoo Chicago senior vice president of programs and impact, said. “This calf’s birth brought hope and joy, and his sudden loss reminds us of the delicate balance of life.” 

Zoo officials said the calf, who was under continual 24-hour, minute-to-minute observation by the Zoo’s animal care and veterinarian teams, had been exhibiting positive and progressive indicators of development up until his death.

The calf had been meeting all milestones, including healthy levels of nursing and other activities, and his mother, a 38-year-old bottlenose dolphin named Allie, was also providing appropriate maternal care, Dr. Stacey said.

But things rapidly changed on Wednesday evening when staff members witnessed a rapid, unexpected change in the calf’s behavior. Officials said within minutes of noticing the change, the calf died.

While the cause of death is unknown, zoo officials said a dolphin calf’s first year of life is full of milestones that must be reached and even slight developmental challenges can become critical in a short time.

In the wild, one in five calves born to first-time mothers do not survive their first year.

“The first few days after birth are a vulnerable, critical timeframe for dolphin calves,” Dr. Rita Stacey said. “This is a devastating loss for our Zoo community, especially the animal care and veterinary teams who dedicate their lives to the well-being of animals in our care. They provided exceptional, around-the-clock care to Allie and her calf. While the calf was progressing well, dolphin neonates face immense biological challenges. We are deeply saddened by his sudden passing.” 

The calf’s mother, as well as the rest of the dolphin group, are now being closely monitored by animal care and veterinary staff.

Officials said while the loss of the calf is devastating, dolphin births, which are rarely observed in the wild, contribute to the zoo’s scientific understanding of dolphin neonatology and care.

“Brookfield Zoo Chicago is one of only a few institutions globally with the expertise, resources and scientific partnerships capable of contributing to meaningful advances in marine mammal care and conservation,” a zoo official said in a release on Thursday morning.

The zoo is now awaiting a complete necropsy to determine the calf’s cause of death.