The other animals which try to sneak off in such manner as to escape observation approach more or less closely to the ideal which the cats most nearly realize.  Wariness, sharp senses, the habit of being rigidly motionless when there is the least suspicion of danger, and ability to take advantage of cover, all count.  On the bare, open, treeless plain, whether marsh, meadow, or upland, anything above the level of the grass is seen at once.  A marsh-deer out in the open makes no effort to avoid observation; its concern is purely to see its foes in time to leave a dangerous neighborhood.  The deer of the neighboring forest skulk and hide and lie still in dense cover to avoid being seen.  The white-lipped peccaries make no effort to escape observation by being either noiseless or motionless; they trust for defence to their gregariousness and truculence.  The collared peccary also trusts to its truculence, but seeks refuge in a hole where it can face any opponent with its formidable biting apparatus.  As for the giant tamandua, in spite of its fighting prowess I am wholly unable to understand how such a slow and clumsy beast has been able through the ages to exist and thrive surrounded by jaguars and pumas.  Speaking generally, the animals that seek to escape observation trust primarily to smell to discover their foes or their prey, and see whatever moves and do not see whatever is motionless.

By the morning of January 5 we had left the marsh region.  There were low hills here and there, and the land was covered with dense forest.  From time to time we passed little clearings with palm-thatched houses.  We were approaching Caceres, where the easiest part of our trip would end.  We had lived in much comfort on the little steamer.  The food was plentiful and the cooking good.  At night we slept on deck in cots or hammocks.  The mosquitoes were rarely troublesome, although in the daytime we were sometimes bothered by numbers of biting horse-flies.  The bird life was wonderful.  One of the characteristic sights we were always seeing was that of a number of heads and necks of cormorants and snake-birds, without any bodies, projecting above water, and disappearing as the steamer approached.  Skimmers and thick-billed tern were plentiful here right in the heart of the continent.  In addition to the spurred lapwing, characteristic and most interesting resident of most of South America, we found tiny red-legged plover which also breed and are at home in the tropics.  The contrasts in habits between closely allied species are wonderful.  Among the plovers and bay snipe there are species that live all the year round in almost the same places, in tropical and subtropical lands; and other related forms which wander over the whole earth, and spend nearly all their time, now in the arctic and cold temperate regions of the far north, now in the cold temperate regions of the south.  These latter wide-wandering birds of the seashore and the river bank pass most of their lives in regions