The Florida manatis are extremely mild and inoffensive animals, seeming never to fight one another, nor to show aggressiveness of any kind. When not molested they are very gentle and will feed close about a boat or dock regardless of the presence of people, but they become alarmed by any sudden noise. In captivity they soon learn to eat from their captor’s hands. Manatis are sluggish, stupid animals, without other defense than their size. They are not rapid swimmers and are among the extremely few herbivorous aquatic mammals. Unlike seals, whales, and their allies, which feed upon some form of animal life, manatis feed on the lush grasses and other vegetation springing from the oozy bottom of the waters they frequent. When feeding on the bottom they use their flippers to help move slowly about. In places along the Indian River they are reported to approach the shore and, with head and shoulders out of water, to feed on heavy grasslike plants hanging from the banks. [Illustration: MUSK-OX] While they are feeding the heavy bi-lobed upper lips work freely and are sufficiently prehensile to seize the grass, or other plant food, between the lobes and thrust it back into the mouth. The ends of the flippers are sometimes used to help convey food to the mouth, like huge hands in thumbless mittens. [Illustration: FLORIDA MANATI] When suckling her young the manati rises to the surface, her head and shoulders out of the water, and with her flippers holds the nursling partly clasped to her breast. This semi-human attitude, together with the rounded head and fishlike tail, may have furnished the basis on which the ancients built their legends of the mermaids. KILLER WHALE (Orcinus orca) The killer whale is a habitant of all oceans from the border of the Arctic ice fields to the stormy glacial margin of the Antarctic continent. So far as definitely known, there appears to be but a single species. It attains an extreme length of approximately 30 feet and is mainly black with well-defined white areas on the sides and underparts of the body. Its most striking and picturesque characteristic is the large black fin, several feet long, standing upright on the middle of the back. The killer usually travels and hunts in “schools” or packs of from three to a dozen or more individuals. Unlike most whales, the members of these schools do not travel in a straggling party, but swim side by side, their movements as regularly timed as those of soldiers. A regularly spaced row of advancing long black fins swiftly cutting the undulating surface of the sea produces a singularly sinister effect. The evil impression is well justified, since killers are the most savage and remorseless of whales. The jaws are armed with rows of effective teeth, with which the animals attack and devour seals and porpoises, and even destroy some of the larger whales.