98 



THE BATS. 



ferior to swallows in rapidity and strength 

 of wing, or in the power of sudden turning, 

 and like these, rise high in the air to fight 

 even with storms. In them the ratio of the 

 length of the fifth to that of the middle digit 

 is respectively lo : i8 and lo : 17, while in 

 the rather helpless horse-shoe bats [Rkino- 

 lophus), which keep fluttering about in the 

 lower regions of the atmosphere, and in the 

 water-bats ( Vespertilio dasycnema and others) 

 the proportion is only 10 : 12. 



The flying membrane itself is always very 

 thin, composed of two delicate layers of skin, 

 between which run blood-vessels, elastic fibres, 

 and a very remarkable nervous tissue. To 

 the naked eye it appears perfectly hairless, 

 while the rest of the body is thickly covered 

 with hair, but it has, in fact, a large number 

 of delicate little hairs scattered over it, which, 

 as is proved by the little bundles of nerves at 

 their roots, act as highly sensitive end-organs 

 of touch. 



The feet are constructed on the normal 

 type, always short and powerful, the five toes 

 quite free, and armed with strong sickle- 

 shaped claws. When resting, the bats either 

 hang by the feet with the head downwards or 

 by the clawed thumb of the fore-limb. At 

 the ankle there is usually developed a spur 

 which is directed inwards, and is always 

 very thin, but often, at the same time, re- 

 markably long, and this spur serves to sup- 

 port the expanded membrane between the 

 feet and tail. 



Of the senses, that of touch is the most 

 highly developed. Bats which have had 

 their eyes sealed, or even picked out, fly 

 about amidst outstretched threads and other 

 obstacles without striking against them with 

 as much ease and security as if they could 

 see. In many species the small eyes are so 

 hidden amongst the hair that keen vision is 

 certainly impossible, and yet they can catch 

 flying insects. Without doubt they are made 

 acquainted with the presence of external ob- 

 jects by the sense of touch even before they 



come in actual contact with them. This sense 

 is developed in all the naked parts — ears, 

 nose, and flying membrane. 



If the sense of sight is weak, that of smell 

 must be regarded as almost equal to zero. 

 Bats which are accustomed to milk and flesh 

 are unable to find out these articles by the 

 nose, and if a high development of this sense 

 has been inferred from the size of the nasal 

 appendages, that inference was based on 

 error, for no animal smells with the outer 

 nose, which is capable of receiving only im- 

 pressions of touch. 



Hearing, on the other hand, is extra- 

 ordinarily keen and delicate, and, unquestion- 

 ably, bats can hear tones which are inaudible 

 to our ears. This is proved even by the voice 

 of most of the native species; its pitch is so 

 high that many persons cannot hear it at all, 

 while the bat perceives it at great distances, 

 and by means of it attracts and warns its 

 fellows. Recently it has been rendered very 

 probable that many insects utter sounds which 

 man cannot hear, but which are, without 

 doubt, audible to the bat. Many insects 

 have a flight quite inaudible to man, by 

 which, nevertheless, a bat is even awakened 

 out of sleep. 



The mental endowments of the bats can 

 only be reckoned at a very low level. The 

 brain has no convolutions, as is usually the 

 case with small animals. The hemispheres 

 of the large brain (the cerebrum) neither 

 cover the mid-brain nor the cerebellum, and 

 are accordingly only very slightly developed. 

 Yet their capacities are adapted to the con- 

 ditions of their existence. They show what 

 seems like great ingenuity in selecting their 

 retreats; they know their hunting-ground, if 

 we may so speak, as accurately as possible. 

 Some species can be tamed to a certain ex- 

 tent. 



If their mode of life and their qualities are 

 not accurately known, that is mainly because 

 they are all nocturnal animals, and our Euro- 

 pean species, which are still those best known 



