104 The Naturalist in La Plata. 



Assuming that these two young bats had, before 

 I found them, existed like parasites clinging to the 

 parent, their adroit actions when liberated, and 

 their angry demonstrations at my approach, were 

 very astonishing ; for in all other mammals born 

 in a perfectly helpless state, like rodents, weasels, 

 edentates, and even marsupials, the instincts of 

 self-preservation are gradually developed after the 

 period of activity begins, when the mother leads 

 them out, and they play with her and with each 

 other. In the bat the instincts must ripen to per- 

 fection without exercise or training, and while the 

 animal exists as passively as a fruit on its stem. 



I have observed that the helpless young of some 

 of the mammals I have just mentioned seem at first 

 to have no instinctive understanding of the lan- 

 guage of alarm and fear in the parent, as all young 

 birds have, even before their eyes are open. Nor 

 is it necessary that they should have such an 

 instinct, since, in most cases, they are well con- 

 cealed in kennels or other safe places ; but when, 

 through some accident, they are exposed, the want 

 of such an instinct makes the task of protecting 

 them doubly hard for the parent. I once surprised 

 a weasel (Galictis barbara) in the act of removing 

 her young, or conducting them, rather ; and when 

 she was forced to quit them, although still keeping 

 close by, and uttering the most piercing cries of 

 anger and solicitude, the young continued piteously 

 crying out in their shrill voices and moving about 

 in circles, without making the slightest attempt to 

 escape, or to conceal themselves, as young birds 

 do. 



