Marine mammologists at the National Aquarium in Baltimore are taking a happy, but cautious approach to the apparent pregnancy of two bottlenose dolphins at the new Marine Mammal Pavilion.
"I think we're all very happy," said Doug Messinger, marine mammal curator at the aquarium. "I don't think we could have hoped for more after having the animals here for less than a year. We can definitely count our blessings."
Nevertheless, he said, "We'll be very cautious about this."
One of the females -- Hailey -- has never borne a calf before, he said, and "there tends to be a very high mortality rate with first-time calves, both in the wild and in captivity."
"There is a fairly high mortality rate with these animals in the first month of life also," Messinger said.
"Once the baby is born, they are very fragile, and there isn't much you can do as far as intervention if there is a problem," he said. "It's in the mother's flipper, so to speak."
With the second female, Shiloh, "we are a little more optimistic," Messinger said. She has been a mother before and her calf, now almost 2 years old, is in a Florida display.
If all goes as expected, Hailey and Shiloh, both 11-year-old, 300-pound females, will deliver single calves next February or March after 12 months of pregnancy, the aquarium announced yesterday.
Baby bottlenose dolphins are typically 2 1/2 to 3 feet long and weigh 25 to 35 pounds.
It's not clear which of the aquarium's two male bottlenose dolphins -- Nalu or Akai -- impregnated the females. But Messinger intends to find out through genetic testing after they're born "so we can mix and match and avoid any inbreeding in the future."
The third female, Nani, appeared involved in the mating activity, but blood tests show no sign of pregnancy. One of her two earlier pregnancies ended in stillbirth, the second in the calf's death from a viral infection after two weeks of life.
Messinger said the dolphins will be left together for now. The females will receive regular prenatal care, with vitamins and other nutritional supplements, more physical exams and sonograms as often as once a month.
"But as the time grows closer, we will probably separate the females from the males," Messinger said.
"It is common for the males to play a little too roughly with a newborn calf," Messinger said. "We probably will not reintroduce them until several months after the baby is born, but they'll have visual and vocal contact."
Dolphin specialists at the aquarium began to have real hope for their breeding program in late February, when the animals began mating activity that Messinger described as "extensive and almost disruptive to our presentations for several weeks."
Successive blood tests during the past six weeks have revealed high hormone levels that indicate pregnancy.
"We still want to do one final diagnosis with ultrasound to try to locate the fetus' heart," he said. "In that way we would definitely [know we] have pregnant animals. But we're pretty confident that we do."
An average of 19 bottlenose dolphins are born in captivity each year at oceanariums in the United States, Messinger said. He attributed the quick results of the Marine Mammal Pavilion's breeding program to a good "social group" of animals and good nutrition.
A successful breeding program in Baltimore would go a long way toward erasing the reputation the National Aquarium had acquired as an unhappy place for dolphins.
The aquarium's main display tank was first renovated, then abandoned as a place to exhibit dolphins when several animals sickened and two died after several months in the tank. Veterinarians diagnosed the problems as a mix of pre-existing conditions and stress brought on by over-exposure to humans and a noisy tank.
The aquarium did not attempt to display bottlenose dolphins again until the completion of its new $35 million Marine Mammal Pavilion last year.