60 ANIMAL INTELLIGENCE 



noticed in a large number of rodents.* The well- 

 known note of the Chipmunk, from which it has 

 derived its name, is the only one I have heard from it. 

 After studying a colony of Eed Squirrels for some 

 weeks last summer, I came to the conclusion that they 

 have a capacity of vocal expression much greater than 

 is commonly believed. Their usual " barking," or trill- 

 ing, seems to be the commonest, the most instinctive, 

 and not largely expressive of anything beyond general 

 satisfaction ; but, I found that, under excitement, there 

 were many other tones, associated with great complexity 

 of emotion, which I am not prepared to analyse, but 

 which there can be little doubt the creatures themselves 

 employ as a means of inter-communication. Under 

 marked excitement, as the result of repeated inter- 

 ferences, I have heard a Ked Squirrel so mingle tones 

 of a musical kind that, a stranger arriving on the spot, 

 would certainly have been deluded into the belief that 

 he was listening to some bird, or rather to an excited 

 pair of birds. The musical character of this combina- 

 tion, together with its continuity and complexity, would 

 perhaps justify the designation "song." One of the 

 writers on musical mice refers to their singing but 

 little in certain instances, except when excited, which 

 is a point of analogy with the Chickaree. 



It would appear, therefore, that it is likely that 

 throughout the order Eodentia a genuine musical 

 appreciation and executive capacity exists, and, in some 

 instances, in a very high degree ; and that apart from 

 this, there is also considerable ability displayed in the 

 expression of states of emotion, at least, by vocal forms. 

 Manifestly, the degree to which animals can express 

 their psychic states and especially in vocal forms is 

 a matter of the greatest importance, and I have already 



* See especially Nature, vol. xv. ; Popular Science Monthly, vol. i. ; 

 and the American Naturalist. 



