The teeth of a crab-eating seal “are surmounted by perhaps the most complicated arrangement of cusps found in any living mammal."[64] The mouth is so arranged that the teeth of the upper jaw fit into those of the lower, and “the cusps form a perfect sieve ... a hitherto unparalleled function for the teeth of a mammal."[65] The food of this seal consists mainly of Euphausiae, animals much like shrimps, which it doubtless keeps in its mouth while it expels the water through its teeth, like those whales which sift their food through their baleen plates.”  This development of cusps in the teeth of the [crab-eating seal] is probably a more perfect adaptation to this purpose than in any other mammal, and has been produced at the cost of all usefulness in the teeth as grinders.  The grit, however, which forms a fairly constant part of the contents of the stomach and intestines, serves, no doubt, to grind up the shells of the crustaceans, and in this way the necessity for grinders is completely obviated."[66]

The sea-leopard has a very formidable set of teeth suitable for his carnivorous diet.  The Weddell, living on fish, has a more simple group, but these are liable to become very worn in old age, due to his habit of gnawing out holes in the ice for himself, so graphically displayed on Ponting’s cinematograph.  When he feels death approaching, the crab-eating seal, never inclined to live in the company of more than a few of his kind, becomes still more solitary.  The Weddell seal will travel far up the glaciers of South Victoria Land, and there we have found them lying dead.  But the crab-eating seal will wander even farther.  He leaves the pack.  “Thirty miles from the sea-shore and 3000 feet above sea-level, their carcases were found on quite a number of occasions, and it is hard to account for such vagaries on other grounds than that a sick animal will go any distance to get away from its companions"[67] (and perhaps it should be added from its enemies).

Often the under sides of the floes were coloured a peculiar yellow.  This coloration is caused by minute unicellular plants called diatoms.  The floating life of the Antarctic is most dense.  “Diatoms were so abundant in parts of the Ross Sea, that a large plankton net (18 meshes to an inch) became choked in a few minutes with them and other members of the Phytoplankton.  It is extremely probable that in such localities whales feed upon the plants as well as the animals of the plankton."[68] I do not know to what extent these open waters are frequented by whales during the winter, but in the summer months they are full of them, right down to the fringe of the continent.  Most common of all is the kind of sea-wolf known as the Killer Whale, who measures 30 feet long.  He hunts in packs up to at least a hundred strong, and as we now know, he does not confine his attacks to seal and other whales, but will also hunt man, though perhaps he mistakes him for a seal.  This whale is a toothed