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  ANNUAL 
  REPORT 
  SMITHSONIAN 
  INSTITUTION, 
  1922. 
  

  

  The 
  entire 
  phenomenon 
  of 
  canal 
  building 
  by 
  beavers 
  is 
  surely 
  

   worthy 
  of 
  a 
  far 
  more 
  intensive 
  study 
  by 
  observers 
  trained 
  in 
  modern 
  

   methods 
  of 
  the 
  investigation 
  of 
  animal 
  behavior 
  than 
  has 
  yet 
  been 
  

   given 
  it. 
  When 
  such 
  sporadic 
  observations 
  as 
  the 
  few 
  which 
  have 
  

   been 
  made 
  include 
  so 
  much 
  of 
  more 
  than 
  ordinary 
  interest, 
  a 
  

   genuinely 
  exhaustive 
  investigation 
  could 
  hardly 
  fail 
  being 
  fruitful. 
  

   It 
  is 
  because 
  prior 
  to 
  so 
  desirable 
  a 
  consummation 
  even 
  relatively 
  

   minor 
  contributions 
  may 
  prove 
  of 
  interest 
  that 
  these 
  notes 
  have 
  been 
  

   published. 
  At 
  least 
  one 
  basal 
  fact 
  seems 
  to 
  be 
  pretty 
  thoroughly 
  

   established: 
  These 
  artificial 
  waterways 
  are 
  constructed 
  primarily 
  

   for 
  the 
  transportation 
  of 
  food, 
  thus 
  bearing 
  an 
  analogy 
  to 
  the 
  more 
  

   pretentious 
  canals 
  of 
  human 
  construction, 
  and, 
  like 
  the 
  latter, 
  they 
  

   appear 
  to 
  be 
  only 
  secondarily 
  utilized 
  for 
  the 
  transportation 
  of 
  

   building 
  materials, 
  for 
  the 
  diversion 
  of 
  needed 
  or 
  superfluous 
  water, 
  

   or 
  as 
  simple 
  thoroughfares 
  for 
  the 
  beavers 
  themselves. 
  I 
  would 
  

   not 
  deny 
  that 
  there 
  are 
  sometimes 
  individual 
  canals 
  which 
  situation 
  

   or 
  other 
  circumstances 
  quite 
  conclusively 
  indicate 
  to 
  have 
  been 
  in- 
  

   tended 
  largely 
  or 
  wholly 
  for 
  one 
  or 
  the 
  other 
  ordinarily 
  subsidary 
  

   purposes 
  last 
  mentioned. 
  Indeed 
  several 
  such 
  examples 
  have 
  been 
  

   cited 
  bj' 
  Mills, 
  4 
  in 
  a 
  volume 
  which 
  contains 
  quite 
  the 
  best 
  account 
  of 
  

   this 
  phase 
  of 
  beaver 
  activity 
  that 
  I 
  have 
  been 
  fortunate 
  enough 
  

   to 
  encounter. 
  But 
  this 
  does 
  not 
  gainsay 
  that 
  the 
  primal 
  urge 
  back 
  

   of 
  all 
  this 
  cerebral 
  activity, 
  whether 
  or 
  not 
  any 
  degree 
  of 
  intelligent 
  

   control 
  of 
  the 
  instinct 
  be 
  admitted, 
  is 
  that 
  of 
  food 
  getting. 
  

  

  The 
  aspen, 
  or 
  quaking 
  asp 
  (Populus 
  tremuloides 
  Michx.) 
  , 
  is 
  said 
  to 
  

   be 
  the 
  tree 
  the 
  bark 
  of 
  which 
  is 
  most 
  keenly 
  sought 
  by 
  the 
  beaver 
  

   as 
  food, 
  but 
  in 
  the 
  absence 
  of 
  the 
  aspen 
  various 
  other 
  species 
  of 
  the 
  

   Salicacese, 
  notably 
  certain 
  of 
  the 
  cottonwoods 
  and 
  willows, 
  with 
  per- 
  

   haps 
  one 
  or 
  two 
  other 
  trees, 
  seem 
  to 
  serve 
  just 
  as 
  well. 
  However 
  

   that 
  may 
  be, 
  once 
  the 
  supply 
  immediately 
  adjacent 
  to 
  the 
  winter 
  

   feeding 
  basin 
  has 
  become 
  depleted, 
  the 
  simplest 
  recourse 
  (for 
  the 
  

   beaver) 
  is 
  to 
  push 
  his 
  foray 
  farther 
  afield, 
  and, 
  as 
  even 
  his 
  most 
  faith- 
  

   ful 
  admirers 
  admit 
  him 
  to 
  be 
  far 
  more 
  agile 
  and 
  dexterous 
  in 
  water 
  

   than 
  so 
  heavy 
  and 
  nearsighted 
  a 
  creature 
  can 
  ever 
  be 
  on 
  land, 
  what 
  

   more 
  natural 
  when 
  he 
  wishes 
  to 
  take 
  advantage 
  of 
  a 
  slightly 
  more 
  

   distant 
  forage 
  plot 
  than 
  that 
  he 
  attempt 
  to 
  carry 
  his 
  medium 
  thither 
  

   with 
  him 
  ! 
  Instinctive 
  or 
  intelligent, 
  such 
  resourcefulness 
  must 
  often 
  

   be 
  of 
  survival 
  value 
  to 
  the 
  animal. 
  

  

  For 
  the 
  past 
  five 
  years 
  the 
  writer 
  has 
  had 
  under 
  intermittent 
  obser- 
  

   vation 
  a 
  very 
  long 
  and 
  in 
  some 
  ways 
  unusually 
  highly 
  developed 
  

   beaver 
  canal 
  which 
  is 
  the 
  subject 
  of 
  the 
  following 
  account. 
  It 
  is 
  

  

  ♦Enos 
  A. 
  Mills, 
  In 
  Beaver 
  World, 
  pn 
  77. 
  103, 
  106-107, 
  145, 
  149 
  (1913). 
  

  

  