REPORT OF STATE GEOLOGIST. 



It will be noticed that the bats were placed in the group which 

 have held their own rather than with those which have multiplied. 

 This is because they are so thoroughly adapted to the conditions in 

 which they live that no natural enemies were ever able to prey upon 

 them to a great extent, and they have been neither benefited nor 

 injured by man. 



Since the primeval forest has been almost completely cut down, 

 we might expect that the forest dwelling species would be most 

 affected by man. The above table shows that this is the case. 

 Fifty per cent, of the species have entirely disappeared, almost 

 36 per cent, have diminished in numbers, and the remaining li 

 per cent, have, probably, just held their own. Of the grass in- 

 habiting animals one species, or less than 8 per cent., have been 

 exterminated. The same number has been partly exterminated, 

 four species or about 24 per cent., have about held their own, while 

 about 60 per cent, have probably increased in number. 



On the assumption that species with generalized habits have the 

 advantage, it would seem that the animals living in both forest and 

 field would hold their own better than any others. Examination 

 shows, however, that several of these species are large and others 

 are fur-bearers. Both qualities are a disadvantage to an animal 

 when it comes into conflict with man. Two species, or 8 2-3 per 

 cent., have been exterminated, and the same number have remained 

 stationary. Thirty-six per cent, have materially decreased and 40 

 per cent, have increased. Of the introduced species, two have be- 

 come established and two have not, while no general conclusions 

 can be drawn concerning the others of this category. 



For a clearer understanding of ecological relationships, it seems 

 desirable to consider the individual as apart from the species, al- 

 though it is, of course, impossible for the individual to live in an 

 environment different from that of the species to which it belongs. 



Every animal is thrown into contact with two more or less dis- 

 tinct environmental relations, the biological and the physical. The 

 biological environment includes all of those living things which 

 the animal may seek as food or as a mate, and also such creatures 

 as may seek to use it for food or for a mate. The relationship is 

 therefore an active one and the adjustment of the individual to its 

 })iological environment is a pr()l)lem that, to animals of most species, 

 is ever present, ever changing and never solved. When an animal 

 becomes so pc^rfectly adjusted to its biological environment that 

 effort is no longer required to maintain th(^ balance, the animal's 

 mental faculties c(uis(} to develop. This has happened to many of 



