Shedd Aquarium’s robust baby beluga whale, whose life may hang in the balance if he cannot learn to nurse from his mother soon, exemplifies nature’s brutal rules of survival that science still struggles to understand.
It may be that the Shedd’s four-day-old whale, which had not begun nursing by late Monday, simply has the bad luck of being the firstborn of 13-year-old Puiji (poo-EEE-jee). A body of scientific literature suggests the firstborn in many animal species–especially marine mammals like whales and dolphins– are expendable, that often the majority of them don’t survive in captivity or in the wild.
It is as if the first attempt at reproduction is a practice run that helps the mother accumulate knowledge and strength that she will need to assure that her later babies have a better chance at survival. Researchers in the wild and in zoos see this first-born phenomenon in marine mammals, land mammals and even birds, whose first clutches often contain improperly formed eggs, or eggs that fail to hatch because bewildered first-time parents don’t properly incubate them.
At the Shedd, keepers say that Puiji displays all the correct maternal behavior, bonding to her strong-swimming infant. But her baby as of Monday still had not grasped her lessons in diving, which he needs to do to locate and suckle from her mammary glands.
“With marine mammal calves, it’s the infant’s responsibility to find the mother’s mammaries,” said Brian Joseph, veterinarian and general curator at Point Defiance Zoo, in Tacoma, Wash. “If you think about it, it’s a much more complicated proposition than with land-based mammal babies finding their mother’s nipples. Whale babies have to move through the water with their mothers while they nurse.”
In fact, whale nursing requires so much good timing in relationship to the mother’s and baby’s movements that Joseph compared it to “the same complexity of docking into a space shuttle”: It has to dive with a proper amount of stored breath, find one of two mammary glands on the mother’s underside protruding slightly from slits, glide in at the proper speed and latch on and suckle while riding in the slipstream of the mother’s wake.
“If the baby can’t learn to nurse,” said Joseph, “it may mean there may be something wrong with the baby.” The first baby beluga born at the Shedd, last year, died within hours because it was too weak to swim.
Because the process is so complex, human divers can’t simply grab the infant and show it to the mother’s nipple, said Deb Fassnacht, a Shedd vice president. It’s likely that such a maneuver might scare Puiji into thinking the divers were going to harm the baby, so they wouldn’t try it, anyway, Fassnacht said.
Puiji’s offspring Monday did show some indications it might be learning.
“Our animal care staff reported that several times during the day the calf was moving around his mother like he was looking for a place to nurse,” said Fassnacht, “but he still never actually nursed.”
As a stopgap measure, keepers are giving the infant an artificial formula twice a day. The simulated whale’s milk, however, may be the only strategy left to keep the baby alive if it does not nurse within the next few days. Whether the calf can survive on formula, a tactic never tried before with captive beluga babies, remains in doubt.
Why only 50 percent or fewer of first-time babies survive among marine mammals both in captivity and the wild, may be linked in part to tremendous demands infants make on females–a fact that would not surprise human parents.
“Lactating is the most stressful time physiologically in any female mammal’s lifetime,” said Dan Costa, a University of California-Santa Cruz biologist who specializes in marine mammals.
“Because of the amount of energy needed to produce milk, the females have to increase their intake of food and their energy expenditure more than at any other time in their life. Ask any mother with a lot of kids; it’s a lot of work.
“Marine mammals differ from land mammals in that they never stop growing in their lifetime. The bigger, fitter marine mammal mothers tend to be the older mothers, and young, first-time mothers tend to be smaller and weaker.”
Beluga mothers may not have a surviving infant until their late teens or 20s.
Much of a newborn’s survival also depends on the mother’s maternal abilities learned from life experience, Costa said.
“Having gone through the experience,” Costa said, “an older female has an easier time of it, knowing what to expect. Human women who have raised kids, the second time around is a lot easier.”
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If anything, learned behavior may be even more crucial for wild animals than for zoo and aquarium animals, said Joseph.
“A lot of survival is learned behavior,” he said, “learning to nurse, learning to follow mom, learning to avoid predators. Most wild animals have a tough time living to be one year old. Even with the big, tough African lions, only one out of 10 lives to be one year old.
“Most of the time we live in a never-never land thinking everything that is born should live. It doesn’t happen that way.”
With captive animals, said George Rabb, director of Brookfield Zoo, human intervention can sometimes improve nature’s survival odds.
“Some animals we’ve actually helped. We’ve actually trained first-time gorilla and orang(utan) mothers-to-be in terms of appropriate maternal behavior to help them to get used to a strange little thing that will soon be pulling on their breasts.”
Many circumstances that kill babies in the wild can be averted in zoos. An injured or ill zoo animal gets medical attention, for example.
After any zoo birth, Rabb said, keepers are very attentive to see if the mother knows what to do and if it is going to accept or reject the baby. Rejected babies get pulled from the mother for hand-raising.
“One of the things you worry about in all these (hand-raising) cases,” said Rabb “is if the infants are going to get through the initial few days of life without the mother’s colostrum, the antibodies found in the first days after the birth in the mother’s milk. Newborns have no developed immune system, and need this as their early protection system.”
Though science knows the immense benefits of mother’s milk, said Joseph, a lot isn’t known about why and how it is so beneficial, so raising babies on artificial formulas is never an attractive option.
“We know the composition of mother’s milk changes all the time according to changing needs in the baby as it grows,” he said, “and that it changes in volume as time goes on, but we don’t know how all that happens.
“The best efforts we can make to help an infant are not as good as the worst efforts of the mom.”