The Bottle-nosed Porpoise (Tursiops truncatus) is the only species of porpoise that has ever been taken at the Hatteras fishery. Our eight-foot specimens represent the average size. A number of animals were measured in November, however, which exceeded nine feet in length. The greatest length for this species at Hatteras is twelve feet, but this is altogether unusual. Measurements and weights taken in November show that a porpoise five and a half feet long weighs 100 pounds; six feet, 160 pounds; seven feet, 200 pounds; and eight feet, 300 pounds.
The movement of porpoises along the great beach which extends in a general southwesterly direction from Cape Hatteras is usually close to the surf. The bands appear to move in both directions. Residents of Hatteras are of the opinion that the majority of those in the vicinity of Hatteras Inlet move to the eastward, turning south from the Cape, whence they gradually swing back to the mainland. They have not, however, been followed away from the beach, and their winter movements are not known with certainty.
Immediately after their capture at Hatteras, where they were brought to land with a large drag-seine, the porpoises were placed for twenty-four hours in a deep salt water pond just back of the ocean beach. Here they had an opportunity to recover somewhat from the fright of capture, and to rest in cool water. No chances whatever were taken in the matter of temperature. On the beach their natural warmth of body would no doubt have been greatly increased by the hot sunshine.
The following day they were seined out of the pond and placed in the shipping tanks, which were then hoisted on board a schooner and at once filled with water. During the voyage through the fresh waters of Pamlico Sound and the Great Dismal Swamp Canal, the water in the tanks was changed whenever it became warm. After reaching the New York steamer at Norfolk the cooling of the porpoise tanks en route was greatly simplified by the use of the steamer’s salt water hose.
The shipping of porpoises alive is therefore a simple matter. The adult animals readily stand transportation, while the young do not. If carried in long, narrow boxes large enough to accommodate them without rubbing, and if kept supplied with sufficient cold water to support and cover them, they can be handled easily enough. There is probably no reason why a porpoise, under such conditions, should not be carried in a tank many times the two days’ journey from Hatteras to New York, although on a journey by rail the changing of the water would be difficult and expensive. While its temperature could be controlled by the use of ice, the water carried without changing would be seriously fouled, for two or three days. The question of food could be disregarded for a few days without injury.
The captive porpoises are very lively and keep swimming day and night, rising to blow usually with each circuit of the pool. Being kept in shallow water, they probably breathe oftener than they would in deep water. They often swim under water, belly up, like seals, but never lie upon the bottom or bask at the surface as the latter do. Visitors ask whether they ever rest—a question not easy to answer. If they do, it is apparently without cessation of forward motion. Nevertheless they are quieter at night when most of the lights are cut off, and do not indulge in boisterous play.
For a time two of them habitually moved from left to right, while three took the opposite course, but this practice soon became less regular and is apparently breaking up. Sometimes the speed is slow, but more often it is rather rapid. Occasionally they indulge in a bit of racing that makes high waves, the water surging up to the coping of the pool. A porpoise speeding around the pool can make a right-angled turn as quickly as a frightened fish, without lessening speed.
When being fed all regularity of movement is abandoned, and they rush in various directions to seize at the surface the fishes slowly thrown into the pool. This continues for some time after feeding, until all sunken scraps are gleaned from the bottom. All food is swallowed under water. Frequently a porpoise will play with a dead fish, thrusting its head clear of the water and throwing the fish from five to ten feet away, when it is recovered and thrown again. Such play may last half an hour, or until the fish is reduced to scraps too small to be thrown. It is not uncommon for two or three of them to be engaged in throwing fishes at the same time and the practice is becoming habitual.
Photo by Dr. C. H. Townsend.
“Immediately after their capture at Hatteras ... the porpoises were placed for 24 hours in a deep salt water pond, just back of the ocean beach. Here they had an opportunity to recover somewhat from the fright of capture, and to rest in cool water.... The following day they were seined out of the pond and placed in the shipping tanks, which were then hoisted on board a schooner and at once filled with water.”