SOLITARY AND GREGARIOUS. 57 



as an ascertained fact; and M. Beauplan goes so 

 far as to imagine that he has seen a party trailing 

 one of their companions by the tail, taking care not to 

 overset him *. This feat, however, seems to be 

 outdone by the one recently given on anonymous 

 authority as authentic, of the marmot's skill in hay- 

 making. " They bite off the grass,'' it is also said, 

 " turn it and dry it in the sun f." 



The only obvious and decided instance of mutual 

 assistance which we recollect as occurring among 

 birds, is that of parents feeding their young, keeping 

 them clean and warm, and defending them against 

 enemies, of all which habits we shall give ample 

 details in the sequel of this volume. But in order to 

 secure warmth, many species certainly take advan- 

 tage of the animal heat of their kindred, and we 

 may with some plausibility say, that in most cases 

 this is done by mutual sufferance, if not by distinct 

 permission. 



It is one of the most extraordinary as well as one 

 of the best ascertained facts in the animal economy, 

 though by no means as yet satisfactorily explained, 

 that the interior heat of warm-blooded animals varies 

 extremely little in the coldest arid in the hottest 

 climates. To the uriinstructed it appears no less 

 erroneous to say that the body is equally warm 

 on a cold winter's morning and on the most sultry 

 of the dog-days, as to affirm that the sun is sta- 

 tionary contrary to the apparent evidence of the 

 senses ; yet the one truth is as well ascertained as 

 the other. For example, Captain Parry found that 

 when the air was from 3 to 32 at Winter Isle, 

 lat. 66 11' N., the interior temperature of the foxes 

 when killed was from 106f to 98 {; and at Ceylon, 

 Dr. Davy found that the temperature of the native 



* Descript. Ukraine. 

 t Mag, Nat. Hist. 1377. J Second Voyage, p. 157. 



