‘Baby whistle’:
Bella’s unusual maternity whistle could be a communication clue, researchers at Six Flags report
A pregnant dolphin at Six Flags Discovery Kingdom seems to be in tune with her unborn calf.
Dolphins are known for their exquisite communication skills, but a late-term, pregnant dolphin at Six Flags Discovery Kingdom in Vallejo may be one of the first discovered vocalizing to her unborn baby.
Bella, a 9-year-old bottlenose, caused a double-take among her trainers a few months ago when they discovered her alone in a pool vocalizing her “baby whistle” — an individual sound that every mother dolphin uses to call her calf immediately after birth.
This signature whistle is used to imprint with babies, or dolphins use it to announce themselves when they come in contact with new dolphins, much in the way a person uses one name throughout their life. It was unusual for Bella to make the sound in her last trimester, before her Jan. 14 due date, because it’s a sound trainers rarely hear in the pool, as all the resident dolphins are too familiar with one another to use name whistles.
“We all noticed it right away; Bella was alone in the pool, floating peacefully, making her baby whistle, and it caught our attention because we all know each and every sound every one of the dolphins make,” said head dolphin trainer Dianne Cameron.
Seven dolphins have given birth at Six Flags in the past two decades, and trainers don’t recall any of them making pre-birth baby whistles.
Bella’s vocalizations have caught the interest of researchers at the Marine Mammal Behavior and Cognition Laboratory at the University of Southern Mississippi, one of the nation’s top dolphin behavior research centers.
“We don’t know how unusual Bella is, because there is virtually no research out there about how newborn dolphins learn to communicate,” said laboratory director Stan Kuczaj. “It’s a big ocean and impossible to study this in the wild.”
The pools at Six Flags were built with research in mind — a large, round birthing pool has a wall of windows and deck holes where researchers can lower underwater hydrophones to record Bella’s acoustics. They are using GoPro cameras to gather an hour of Bella video daily to send back to Kuczaj’s laboratory, so he and his graduate research assistants can study Bella’s behavior. They will continue to record Bella after she delivers to see how she communicates with her calf.
‘Better conclusion’
“If Bella makes the same whistle after her baby is born, then we can draw a better conclusion that she was making early vocalizations to her baby,” said HolleyMuraco, a marine mammal reproductive physiologist who is in charge of all births, and all contraception plans, at the park.
While MRI scans show that fetal dolphins have the ability to vocalize in the womb, and have mature nasal air sacs, vocal chords and skull structures, it’s unknown whether they can hear their mothers, or respond in any way.
But the implications for dolphin research are huge. If researchers can find out more about how pregnant dolphins communicate with their babies, marine conservationists already calling to quiet down the oceans to protect humpback whale breeding grounds would have more of an argument that noise pollution from shipping is harming sea life.
“There’s so much interest in sound in the ocean,” Muraco said. “If we know babies need to listen to their moms, it will have a huge environmental impact by letting us know that, ‘Hey, we have to quiet down.’ ”
Each week, Bella swims to the side of the pool and rolls on her back so Muraco can conduct an ultrasound, using an industrial strength, military-issue machine designed to look for internal bleeding in the field.
Inside peek
During the first week of January, Muraco rubbed the paddle over Bella’s lower abdomen and spotted the heart beating, the ribs, the eye and “a male part.”
“Look, you can see her mammary glands are swollen, too,” Muraco said, pointing to two tearshaped sacs of milk the size of papayas.
Adam Gilbert, Bella’s primary trainer, takes Bella’s temperature daily. Once it drops 2 degrees below her typical 98.2, that’s an indicator she will deliver in about 48 hours. Once the mercury drops, Gilbert and his colleagues will keep a 24-hour vigil in shifts — inside a tent outside the birthing pool — looking for the baby’s tail to emerge from Bella’s underside.
“This has the potential to be really exciting,” he said of the research possibilities of watching Bella teach her calf to communicate.
“Bella is by far our smartest dolphin,” he said. “By the time she was 2, she taught herself how to flip in the air just by watching the others. It makes sense that she might also be doing something unusual and smart as she becomes a mother for the first time.”