26 



BLIND VERTEBRATES AND THEIR EVES. 



THE CAVE RAT AND ITS EYES. 1 



The cave rat, Xn>tinna master, ranges eastward to southern New York and 

 south to Alabama, and is not confined to caves. It lives in "cliffs, caves, and rock 

 ledges of the mountains, descending into the lowlands, where limestone caves afford 



it security." 



In White's Cave, near Mammoth Cave, Kentucky, it has its nests near the 

 entrance, in the twilight region. In Mammoth Cave I found it in Mammoth Dome, 

 and it occurs also farther in, far removed from the twilight area. 



Rhoads (Jour. Cin. Soc. Nat. Hist., xix, No. 2, 55, 1897) says of it: 



Any suspicion of blindness or deficient eyesight, such as is exemplified in some of the lower 

 orders of animal life in the cave, can not attach to this mammal. As in all the more strictly noc- 

 turnal rodents, the eyes of this species are greatly developed ; nevertheless, they are able to make 

 most intelligent use of them in broad daylight, if need be. 



In his "Origin of Species," sixth edition, vol. i, page 171, Darwin says that 

 the eyes of Neotoma of Mammoth Cave are "lustrous and of large size; and these 



FIG. i. (a) Eye of Mammoth Cave Rat. (/) Eye of Common Gray Rat. 



animals, as I am informed by Professor Silliman, after having been exposed for 



aboul a month to a graduated light, acquired a dim perception of objects." The 



ratj .\foloniii, is still abundant in Mammoth Cave. Its tracks are numerous, 



and in plans little paths have been made by the rats where they run backward 



d forward along ledges of rock. Since, however, a track once made in a cave 



unchanged by wind or weather, the abundance of rats, as judged by their 



;, may be misleading. A number of traps were set in the rotunda. During 



trap was sprung and one had the bait removed. No rats were 



caught in the traps and none were caught alive. The author discovered one rat 



rolling a mouse trap about which was too small for it to enter. When approached 



I, the rat turned about and stared at the light. It then ran to a pile of 



but did : 'ipt to hide; instead, the rat ran to one end of the pile, then 



alon-j; the top hack to when- it had stood, then stopped and again stared at the light. 



Dr. J. B. Slonakor's account, from which figures I and 2 are 

 l"'l. Ac.ui . 25S| ,899. 



