610 NATURAL HISTORY. 



Bats. 



The beats are the only true flying mammals. The colugo, the flying- 

 squirrel, and the like do not really fly; they merely slide down an inclined 

 plane of air, and their "flight ' always terminates at a lower level than 

 that which they started from. It is true that they can rise above the 

 lowest part of the course ; but this is due not to any volant powers, but to 

 the momentum they gained in their previous descent. In the bats, on the 

 other hand, we have flying powers as well developed as in the insects and 

 birds. Here true wings are found which need a moment's attention. 



Such a thing as a bat's wing is not paralleled in the whole living 

 animal world. Its thin, skinny appearance is very disagreeable, and it is 

 notable that when artists wish to picture a griffin or goblin, or other horri- 

 ble creature of the imagination, the wings of a bat are almost invariably 

 appended to complete the idea. A glance at our cut will show some fea- 

 tures of interest in relation to these wings. In the birds the wing is formed 

 by stiff feathers borne on the arm, and the bones of the hand are very 

 degenerate. In the bat, on the other hand, the wing is but a membrane 

 which needs some more solid support, and for this purpose the bones of 

 the hand are highly developed. The fingers especially are very long, and 

 four of them form long rods, having the same relation to the membrane of 

 the wing as the ribs of the umbrella have to the cloth. One of the 

 fingers, however, does not enter into the support of the wing ; but rather 

 serves as a hook or claw — the only substitute for a hand. 



Bats are nocturnal animals, and in our summer evenings, soon after 

 dusk, they appear, sometimes in large numbers, flitting about on noiseless 

 pinions in their search for mosquitoes and other insects of evening. They 

 are apt to inspire feelings of dread ; but needlessly, for there is no danger : 

 they will not touch any one or do the slightest damage. Even in the 

 darkest places they will steer clear of every obstacle, not touching the 

 smallest thing. It is not to sight alone that they owe this skill ; the 

 wings are very sensitive, and are richly supplied with nerves, so that they 

 can feel even the slightest changes in the air — changes which we, with our 

 much duller senses, can hardly conceive of. Most of the bats are to be 

 regarded as beneficial in that they feed on insects, and devour immense 

 numbers of those unmitigated nuisances, the mosquitoes. None that we 

 have with us do the slightest harm, though if caught in the hands, their 

 sharp, needle-like teeth will draw blood from the fingers. 



All of the bats, however, are not insect-eating. There is a group of 

 large forms living in the tropical parts of the Old World which feed 

 solely on fruits. One of these forms is shown in the adjacent plate. From 



