BATS 



(Chiropterd) 



BATS are at once separated from all other mammals by their 

 peculiar modification for flight. The fore-limbs are much elongated, 

 especially the fingers, and a thin extensible membrane stretches 

 over this frame-work, connecting also with the sides of the body 

 and the hind legs. Another membrane stretches between the hind 

 legs, known as the interfemoral membrane. 



Besides their flying apparatus, bats are peculiar in having their 

 hind legs twisted around in such a way that the knee bends back- 

 wards, which render it exceedingly difficult for them to walk, a 

 mere flapping shuffle being the result of their best efforts. On the 

 wing, however, their movements are exceedingly graceful, and they 

 turn and wheel in their varied evolutions with the greatest ease. 



Other structures frequently mentioned in the description of 

 bats are the peculiar leaf-like appendages to the nose and the 

 elongated lobe of the ear or tragus. 



In their general anatomy and in their den- 

 tition, bats show a closer relationship to the 

 insectivora (shrews and moles), and may, indeed, 

 be regarded as a highly specialized off-shoot 

 from that group. 



Bats are distributed in all parts of the world, 

 and vary in size from the small mouse-like 

 species to the big flying foxes of the Malay 

 region, the expanded wings of which measure 

 as much as thirty inches from tip to tip. 



These large bats and their allies are fruit 

 (After Miller) ea ters, but the majority of the species, including 

 all our Eastern American bats, are insectivorous, and feed while 

 on the wing. 



Bats are nocturnal in habits, and seem to be most active at 

 dusk and early in the morning, just before dawn. The hours 

 of day-time they spend at rest, hanging head downward by their 



Ear of Bat, showing 



193 



