Dr. Charles H. Townsend, Director of the New York Aquarium, tells of an interesting experience on the Pribilof Islands, which illustrates the terror in which the killers are held by other water mammals. He was collecting a number of the great Steller’s sea lions for the Smithsonian Institution and was shooting the animals, which were on land, with a repeating rifle. The sea lions began rushing toward the water in terror when suddenly the high dorsal fin of a killer whale appeared a few fathoms offshore. The sea lions stopped short and could not be forced into the water, preferring to face the unknown danger of the rifle rather than certain death in the jaws of an enemy which from earliest babyhood they had been taught to fear. The killer belongs to the dolphin family, of which it is the largest member, reaching a length of from twenty to thirty feet. These animals are found in almost every ocean of the world and, although several species have been described, probably there is but one, _Orca orca_. The dorsal fin of the male is six feet high while that of the female is but three and one-half or four feet, and this has led to the naming of specimens which have proved to be only the male and female of the same species. Killers will apparently eat anything that swims and fish, birds, seals, walrus, whales, and porpoises are all equally acceptable. Their capacity is almost unbelievable, and there is a record of thirteen porpoises and fourteen seals being taken from the stomach of a twenty-one-foot specimen. Dr. Wilson speaks of killers in the Antarctic as follows: Of the whales, the most prominent of all are the Killers, or Orca whales, which scour the seas and the pack-ice in hundreds to the terror of seals and penguins. The Killer is a powerful piebald whale of some fifteen feet in length. It hunts in packs of a dozen, or a score, or sometimes many scores. No sooner does the ice break up than the Killers appear in the newly formed leads of water, and the penguins show well that they appreciate the fact by their unwillingness to be driven off the floes. From the middle of September to the end of March these whales were in McMurdo Strait, and the scars that they leave on the seals, more particularly on the Crab-eating seal of the pack-ice, afford abundant testimony to their vicious habits. Not one in five of the pack-ice seals is free from the marks of the Killer’s teeth, and even the Sea Leopard, which is the most powerful seal of the Antarctic, has been found with fearful lacerations. Only the Weddell Seal is more or less secure, because it avoids the open sea. Living, as it does, quite close inshore, breeding in bights and bays on fast ice some ten or twenty miles from the open water, it thus avoids the attacks of the Killer to a large extent.[12] Footnote 12: “The Voyage of the _Discovery_,” 1905, App., p. 470.