The Indians enter this cave once a year to destroy the young for the sake of a layer of fat, with which the abdomen is covered. These people construct temporary huts at the mouth of the cavern, and melt the fat in pots of clay, over brushwood fires; this fat is called the butter of the guacharo, is transparent, half liquid, without smell, and so pure as to keep more than a year without becoming rancid; the monks purchase this oil of the natives for culinary purposes. Notwithstanding this annual destruction of the birds, their numbers do not sensibly diminish, as it is conjectured that other guacharoes re-people the grotto from neighbouring caves, which are inaccessible to man. The river which runs through the cave, is from twenty-eight to thirty feet in width, and can be traced into the recesses for a considerable distance, the cave preserving its altitude and regular form for 1458 feet; farther than this the river forms a small cascade over a hill covered with vegetation; and surrounded with stalactites; after this ascent the grotto contracts its height to forty feet, still preserving the same dimensions; here the bottom is covered with a black mould on which plants, deposited accidentally by the birds, have vegetated; their characters are however so much changed by want of light and air that it is impossible to recognise the species. Beyond this spot the cries of the birds were so shrill and piercing that no persuasions could induce the Indians to proceed, and M. De Humboldt was obliged unwillingly to return. This subterraneous river is the source of the Rio Caripe, which joining the river Santa Maria a few leagues distant, is navigable for canoes, and falls into the river Areo under the name of Canno de Terezen. The forests of this and of every other part of Cumana are peopled with numerous tribes of monkeys, of which the araguato is the most common and singular; it is three feet in height from the top of the head to the tail, with a reddish brown bushy coat of fur which covers its whole body, being very fine on the belly and breast; its face is of a blackish blue, and covered with a delicate wrinkled skin; the beard long, and its eye, voice and gait, denoting melancholy; when domesticated they have not that vivacity which most monkeys are celebrated for; on the rains, or any sudden change of weather approaching, the howling noises made by this creature are beyond conception dismal, and add, during a storm, to the horrors of the uninhabited wilds in which the traveller finds himself alone, and unprotected.