Advice for expectant mothers: Eat nutritious food, take vitamins and visit the doctor for regular checkups and ultrasound exams.
It's a regimen that Shiloh and Chesapeake adhere to strictly. They take heavy-duty supplements, have experts make ultrasound images of their babies every month and eat 25 pounds of fish every day.
O.K., that's a little more fish than the average human eats - pregnant or not. Shiloh and Chesapeake are two Atlantic bottlenose dolphins who are expected to give birth in late July or August at the National Aquarium in Baltimore.
"All of us are very excited about the calves being born together," Sue Hunter, director of animal programs, said. "The word now is 'suspense,' and we anxiously await the calves' arrival."
The father of the calves is Chinook, a 430-pound adult male on breeding loan from the Minnesota Zoo.
Aquarium veterinarians and staff have been carefully monitoring the animals, who are in good health, and say that they're "cautiously optimistic" about the pregnancies.
Their optimism is always guarded because a third of all dolphin calves do not live to one year of age, in the wild or in captivity.
"There's no room for weak babies," said Dr. Leigh Clayton, director of animal health. "They need to be able to nurse underwater and come up to breathe air. Their coordination, neurological function ... all need to be perfect."
Calves are fragile when they enter the world, dolphin keepers said. They're more susceptible to pneumonia and have weaker immune systems than juvenile dolphins. As a result, expectant dolphins are never induced into labor.
"If they gave birth in September, I wouldn't be shocked," Clayton said. "We tend to be flexible about the due date because the gestational period is just being defined for dolphins."
Dolphins typically carry their young for 10 to 12 months and reproduce every two years. Beginning in July, trainers and volunteers will monitor the expectant dolphins for eight hours a day. In mid-July, the watch will increase to 24 hours until the calves are born.
"We use our existing volunteers because we need the staffing, and it helps to get them involved," said an aquarium spokeswoman, Jen Bloomer. "But there's a possibility that something may not go well. The best-case scenario is two healthy dolphins."
Aquarium volunteers will receive background information on dolphin pregnancies and birthing signs, which include increases in respiration and defecation. Labor itself lasts from 20 minutes to two hours on average, until the calf is born tail-first.
