MARINELAND OF FLORIDA - THE WAY IT WAS

THE FIRST LIVE PORPOISE BIRTH IN CAPTIVITY

On February 26, 1947, a banner day for the founders of the Marine Studios and an exciting one for the biologists who had spent many hours waiting at the portholes, the first porpoise to be born alive in captivity was delivered.

As the hour of delivery approached and the mother withdrew from the school to the side of the tank, the other porpoises grew uneasy, as they do when anything unusual interrupts their routine. Journeying swiftly about the tank they paused to examine her as her labor progressed and then excitedly resumed their swimming. All the while a strange barking, unlike usual porpoise sounds, could be heard in the passageways. At 1:15 p.m. the tail of the infant appeared and at 1:25 the calf fell through. Just as it did so the mother whirled about in a sharp movement that snapped the umbilical cord.

At that very moment the baby, a female, began to swim upward. The mother was directly below her, ready to assist her to the surface, as were two other adult females swimming closely on either side. All the other porpoises were gathered tightly around to protect the mother and infant from several sand-bar sharks that were excitedly milling about because of the blood in the water. When the sharks swam near they were adroitly butted aside by watchful porpoises on the flank of the school. Immediately upon drawing her first breath the infant picked up speed in the quick undulating or galloping motion that is characteristic of porpoises and had no difficulty in keeping up with the rather swift pace of the school.

A little less than an hour and a half later she began to probe the side of her mother for the two nipples hidden in small folds on her underside, and soon she was nursing. Because porpoises are constantly in motion the ordinary nursing apparatus will not do. If the calf were to suckle in the usual manner he would scarcely have time to find the nipple before it was time to rise to the surface for another gulp of air. Nature has accordingly designed the mammary glands so that they secrete milk into little reservoirs where it is stored. When the infant grasps the nipple between his tongue and upper jaw the mother, by contracting certain muscles in her abdomen, can in a few seconds squirt a considerable amount of milk into the baby's mouth. The 1947 calf nursed every fifteen to thirty minutes day and night and at all times swam very close to the mother, generally at her flank.

Continuing their role as midwives and protectors, the two other females conveyed the mother and baby about the tank, devoting most of their energies to chasing away three inquisitive and aggressive males. As the days passed the baby, very thin at birth, filled out rapidly on her diet of rich porpoise milk and gained steadily in strength.

The Marine Studio biologists now knew that the oceanarium was not only a likely, but a most satisfactory place for self-perpetuating school of porpoises. The many births that have since taken place have enabled the staff to add much to their understanding of a realm of aquatic life about which little had been known. They have found that female bottlenosed dolphin may reach sexual maturity at the age of four, bears one infant at a time, the first usually in the spring of her fifth year, and not more than one every other year thereafter. The gestation period is approximately twelve months. The long gestation period enables porpoise young to be well-developed and relatively self-reliant at birth. Labor consumes from a few minutes to almost two hours. The babies, usually three feet long, are born tail first, which is most unusual. But how else could this creature deliver its young? Since porpoises must rise to the surface every minute or so to breathe, the baby would drown if it were born head first. The birth of a porpoise is most critical, requiring almost split-second timing on the part of the mother if she is to turn about quickie, sever the umbilical cord, help her young to the surface for its first breath and successfully start him on his cycle of swimming and breathing. Marineland aquarists know of no animal with so strong a maternal instinct. Concern of a mother for her infant is particularly noticeable when the two are separated. The mother swims frantically about calling to her baby with a high-pitched whistle ( a sound made by forcing air through the blowhole on top of her head) and the baby answers. One mother that had given birth in the receiving tank shortly after her capture , became separated from the infant, a male , by the narrow passage leading from the flume to the circular tank. The youngster had been herded through it but the mother was fearful and would not cross the gate. Upon reaching the oceanarium and finding himself surrounded by strange porpoises, the baby sought the protection of a young female. Whistling loudly, he followed her around the tank at top speed. At this point the distraught mother shot through the gate and rejoined her infant only to be separated from him again, this time by a ring of strange and curious porpoises. The baby did not now seek the company of the young female but remained in the exact spot where he had rejoined his mother, swimming rapidly in a six-foot circle and whistling all the while. It was in the same spot that she found him as soon as she was able to break from the school. When the aquarists observed this same performance on a number of subsequent occasions they became convinced that an instinctive sense of self-preservation tells the infant, when separated from its mother in the open sea, to remain in the exact place where he last saw her. The calf has teeth at birth but they do not erupt through his gums for over a week. A year is generally required to wean the infant completely. Some porpoise young show no interest whatever in solid food for nearly a year, while others have found small pieces of squid palatable at the age of five months. At whatever the age the youngster is weaned the transition from milk to whole fish is difficult. When the mother thinks its time for solid food she brings him a mullet which he toys with cat-and-mouse fashion and likely as not loses it to some other porpoise. When at last he swallows his first fish it usually gives him indigestion. If he vomits, the mother understandingly rubs his stomach with her snout. This procedure is repeated until he manages to keep the mullet down.

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