362 



OSTRICH. 



beautiful provision of nature in the mutual adaptation 

 of her and the desert to each other. Not even the 

 smallest bird, or the bird of the swiftest wing could 

 remain and rear a brood in those more arid breeding 

 places of the ostrich ; and thus, but for her, a large 

 portion of surface upon which she can subsist, would 

 be a waste in nature ; and therefore in opposition 

 to the general laws and provisions of the system. 



In the second place, there are situations, less 

 advanced into the dry desert, where, though the day 

 is exceedingly hot and the air dry, dew forms, and the 

 night is cold, especially toward the morning. When 

 her eggs are in such a situation, the ostrich can afford, 

 with perfect safety to them, to range about for her 

 food during the day. It is necessary, however, that 

 she should come and shelter them with her downy fea- 

 thers during the night, and this she accordingly does. 

 Here again she is enabled to do so from the physical 

 circumstances of the place, because vegetation is much 

 more abundant than in the drier places, and a less 

 range finds her an abundant supply. 



In the third place, ostriches are found in localities 

 without the tropics, and so far out of the desert as that 

 the eggs do not derive so much assistance from the 

 heat of the sun ; and in these the bird requires to sit 

 more constantly, and she does it accordingly. 



Therefore there is not, in the whole range of nature, 

 a more beautiful instance of adaptation than that 

 which subsists between the ostrich and the desert. 

 The desert is a singular locality in nature, and the 

 ostrich is as singularly formed and fitted for the severe 

 labour which it has there to encounter. In its walk- 

 ing structure, the bird is not excelled by any animal, 

 even by those swift antelopes which are her near 

 neighbours. We find too, that wherever one species 

 of action is required in a very high degree, the organ- 

 isation of the animal is to a great extent concentrated 

 upon that. Flight would have been of comparatively 

 little use to such a bird in the situation in which it 

 has been placed by nature. Wings for flight, to bear 

 up so weighty a bird as an ostrich in swift motion 

 through the air, would have demanded a waste of 

 muscular exertion, for the supply of which sufficient 

 food could not have been found in the ostrich's 

 country. Besides, wings would have been of no use 

 in the desert, because there is nothing there which 

 a vegetable feeding bird could catch upon the wing ; 

 and the height of the ostrich, standing on foot, is quite 

 sufficient to reach the top of the tallest vegetable on 

 her pastures. There is therefore a very fine instance 

 of economy in the wings of the ostrich being so little 

 developed as that they are unfit for flight, because 

 this enables the whole power of the bird, in so far as 

 motion is concerned, to be concentrated upon the 

 legs, and the muscles by which these are moved. 



A most essential form of the sternum is obtained 

 by this means. A figure of an analogous sternum, 

 that of the Australian emu, may be seen by referring 

 to page 457, of Vol. I. of this work. From that it 

 will be perceived that the keel, essential to the sternum 

 of a bird of powerful flight is dispensed with ; and 

 also that the principal articulation is with the ribs, 

 while the sternum is a sort of breast-plate on the fore 

 part of the body ; so that the breast can be brought 

 to the ground without any pressure of important parts, 

 in order to enable the bird to fold its very long legs 

 with perfect security, when it is about to repose on 

 the ground. We have no space to go into the parti- 

 culars, but whoever chooses to do so, possessed of 



the proper means of knowledge, will soon perceive 

 that the skeleton of the ostrich is a very fine specimen 

 of animal mechanics. 



The system of nutrition in the ostrich is not 

 unworthy of attention. Subsisting upon vegetable 

 matters, which are hard and dry, and from being so 

 requiring a great deal of grinding, the ostrich has a 

 very strong muscular gizzard, firm and compact in its 

 walls. It may be said to have three stomachs, or at all 

 events there is a dilatation between the crop and the 

 gizzard, which must answer some purpose in the 

 economy of the animal. It is no doubt the necessity 

 of some hard substances to act as a second mill-stone 

 in the gizzard in grinding the food, which makes the 

 ostrich so prone to swallow all manner of hard sub- 

 stances, with perfect indifference as to what may be 

 their taste or their smell. The great length of the 

 intestinal canal too, and the size of the ca3cal append- 

 age, show that the digestion of this animal is a process 

 of the most laborious kind. 



In the matter of sensation, it is probable that the 

 ostrich depends chiefly upon sight. Taste and smell 

 are quite incompatible, either with the finding of the 

 bird's food, or with the swallowing of those substances 

 which assist in the preparation of it. Hearing would 

 also be of comparatively little service in such a bird. 

 The eye is the grand organ upon which the animal 

 depends ; and the length of the neck, which corre- 

 sponds to that of the legs, so that the point of the 

 bill can reach the ground when the axis of the body 

 is in a horizontal position, is well adapted for com- 

 manding a very large surface of the desert. 



In a state of captivity the ostrich prefers grain to 

 every other kind of food, though it will also eat the 

 leaves of lettuce and other succulent plants. In this 

 state it drinks a considerable quantity ; and it is pro- 

 bable that it does so in a state of nature, though the 

 Arabs give a different account of it. There is no 

 doubt that in some of its localities it cannot have very 

 frequent opportunities of drinking, but still there is no 

 ground for believing that it actually abstains from 

 water in cases where it is to be had. 



Though not in the least disposed to be pugnacious, 

 and generally inclined to seek its safety in flight, 

 when it has nothing to protect but its own life ; yet 

 the ostrich is not unprovided with weapons of defence, 

 which it can use with very considerable force and 

 effect. These weapons are the bill, the feet, and the 

 strong spines of which there are two in each wing. 

 The length of the neck, and the powerful motion 

 which it has, enable the bird to use the bill with great 

 velocity ; and we need hardly mention that the velo- 

 city of a striking instrument very rapidly compensates 

 for a deficiency of weight or hardness. We find this 

 proved by the fact, that a tallow candle can be shot 

 through a deal board, if it move fast enough, and also 

 from a circular plate of soft iron, not merely cutting 

 the hardest steel, but even setting it on fire, the plate 

 being moved with great velocity, and the steel held 

 against its edge. The feet also derive a very effective 

 power from their length, and the consequent velocity 

 with which the extremities of them can be made to 

 take effect ; we have remarkable instances of the 

 powerful kick of a long foot in the giraffe, and the 

 kangaroo, the first of which is said to be capable of 

 stunning the lion, and even of breaking his skull, and 

 the second of serving the wild dog of Australia much 

 in the same manner. Thevenot mentions having seen 

 an ostrich lay a dog prostrate by a single backward 



