Brookfield, Ill.— The Chicago Zoological Society staff is mourning the loss of a 7-day-old bottlenose dolphin calf born on December 12 to 9-year-old Allison.

After Allison, a first-time and inexperienced mother, successfully gave birth, the marine mammal care team conducted round-the-clock observations. Most importantly, they monitored the frequency and duration of nursing, and the time that the mother and calf spent swimming closely to each other (slipstreaming), a critical behavior that allows a newborn dolphin calf to conserve energy. After a couple days, the team observed the mother and calf began showing concerning behavioral changes in their swimming patterns. This past Friday, December 19, when it appeared the calf was having increasing problems, the team intervened in order to provide supportive treatment. Despite the efforts by the veterinary and marine mammal staff, the calf died late Friday evening. The team is awaiting complete necropsy results (animal autopsy) to determine if there were other contributing factors.

“It is always a difficult decision, and one never taken lightly, whether or not to intervene when a calf appears to have challenges. One of our goals in animal care is to allow an inexperienced mother the chance to gain maternal experience, which is learned,” said Bill Zeigler senior vice president of collections and animal care for the Society, which manages Brookfield Zoo. “The marine mammal and veterinary team did everything possible to save the calf and is extremely saddened by the loss.” 

Staff members are now focused on the care and well-being of the dolphin group that includes five adult females; two male 1-year-old calves Merlin (mother-reared) and Magic (successfully hand-reared by staff); and a female calf born on December 16.