﻿284 
  ANNUAL 
  REPORT 
  SMITHSONIAN 
  INSTITUTION, 
  194 
  3 
  

  

  believed 
  from 
  experiment 
  that 
  the 
  cells 
  in 
  the 
  pit 
  enable 
  the 
  snake 
  to 
  

   distinguish 
  between 
  cold 
  and 
  warm 
  air 
  currents 
  and 
  hence 
  to 
  know 
  

   when 
  some 
  warm-blooded 
  animal 
  approaches 
  it 
  in 
  the 
  dark 
  — 
  a 
  useful 
  

   function 
  since 
  most 
  pit 
  vipers 
  are 
  nocturnal 
  and 
  do 
  their 
  hunting 
  at 
  

   night. 
  Their 
  food 
  consists 
  of 
  anything 
  small 
  enough 
  to 
  be 
  swal- 
  

   lowed 
  — 
  birds, 
  mammals, 
  sometimes 
  fish, 
  frogs, 
  snakes, 
  lizards, 
  or 
  small 
  

   turtles 
  — 
  each 
  species 
  showing 
  a 
  "preference" 
  for 
  some 
  of 
  the 
  food 
  

   items 
  that 
  it 
  normally 
  can 
  obtain 
  in 
  its 
  own 
  particular 
  environment. 
  

   Most 
  pit 
  vipers 
  are 
  viviparous 
  — 
  that 
  is, 
  their 
  young 
  are 
  born 
  (hav- 
  

   ing 
  developed 
  in 
  the 
  eggs 
  retained 
  within 
  the 
  mother's 
  body) 
  instead 
  

   of 
  being 
  hatched 
  from 
  eggs 
  as 
  is 
  the 
  case 
  with 
  the 
  coral 
  snakes. 
  Young 
  

   snakes 
  begin 
  to 
  look 
  for 
  food 
  very 
  soon 
  after 
  birth. 
  Their 
  skin 
  is 
  

   usually 
  shed 
  within 
  a 
  few 
  days 
  for 
  the 
  first 
  time. 
  

  

  The 
  timber 
  rattler. 
  

  

  First 
  of 
  the 
  more 
  common 
  species 
  on 
  the 
  list 
  for 
  easterners 
  is 
  the 
  

   timber 
  rattlesnake 
  (Crotalus 
  horridus, 
  pi. 
  2, 
  fig. 
  2), 
  also 
  called 
  the 
  

   banded 
  or 
  black 
  rattler. 
  

  

  Distribution 
  of 
  this 
  rattlesnake 
  in 
  the 
  Northeastern 
  States 
  is 
  associated 
  with 
  hills 
  

   and 
  mountains 
  of 
  moderate 
  height, 
  on 
  which 
  there 
  are 
  broken 
  ledges 
  with 
  large, 
  

   loose 
  fragments 
  on 
  the 
  slopes 
  and 
  top. 
  These 
  flat 
  fragments 
  may 
  be 
  a 
  foot 
  or 
  

   more 
  in 
  thickness 
  and 
  from 
  a 
  yard 
  to 
  6 
  or 
  8 
  feet 
  in 
  length, 
  sloping 
  back 
  into 
  

   a 
  fissure, 
  the 
  bottom 
  of 
  which 
  may 
  be 
  covered 
  with 
  soil 
  or 
  leaves, 
  and 
  which 
  pro- 
  

   vides 
  a 
  position 
  of 
  security 
  during 
  storms. 
  It 
  is 
  the 
  common 
  habit 
  of 
  rattle- 
  

   snakes 
  to 
  coil 
  under 
  the 
  edge 
  of 
  these 
  rock 
  masses, 
  protected 
  from 
  the 
  too 
  hot 
  

   summer 
  sun, 
  and 
  ready 
  to 
  quickly 
  retreat 
  if 
  disturbed. 
  If 
  the 
  intruder 
  goes 
  on 
  

   his 
  way, 
  the 
  snake 
  may 
  lie 
  in 
  its 
  motionless 
  coil, 
  without 
  sounding 
  the 
  rattle, 
  

   thus 
  seeking 
  to 
  escape 
  notice. 
  Near 
  these 
  natural 
  homes 
  are 
  specific 
  crevices 
  

   or 
  "dens," 
  where 
  rattlers 
  that 
  have 
  roamed 
  over 
  a 
  considerable 
  area 
  during 
  the 
  

   summer 
  congregate 
  each 
  fall 
  preparatory 
  to 
  deep 
  penetration 
  and 
  hibernation, 
  

   beyond 
  the 
  frost 
  line. 
  During 
  the 
  late 
  summer 
  the 
  females 
  return 
  to 
  such 
  places 
  

   and 
  here 
  the 
  young 
  are 
  born, 
  with 
  a 
  natural 
  instinct 
  to 
  return 
  to 
  this 
  specific 
  

   area 
  each 
  year 
  for 
  winter 
  shelter 
  * 
  * 
  *. 
  4 
  

  

  The 
  diamondback 
  rattler. 
  

  

  The 
  diamondback 
  rattlesnake 
  (Crotalus 
  adamanteus), 
  already 
  men- 
  

   tioned, 
  lives 
  in 
  wooded 
  areas 
  of 
  the 
  Southeast, 
  especially 
  among 
  the 
  

   scrub 
  palmetto 
  of 
  the 
  sea 
  beaches 
  in 
  Florida. 
  "It 
  is 
  not 
  a 
  swamp 
  spe- 
  

   cies, 
  although 
  it 
  may 
  frequent 
  woods 
  close 
  to 
  water 
  and 
  does 
  not 
  hesi- 
  

   tate 
  to 
  swim 
  across 
  small 
  bodies 
  of 
  water. 
  In 
  the 
  coastal 
  strips 
  it 
  

   crosses 
  fair-sized 
  tide 
  pools 
  and 
  has 
  been 
  noted 
  several 
  miles 
  from 
  

   shore, 
  where 
  it 
  has 
  been 
  accidentally 
  carried 
  by 
  the 
  currents. 
  It 
  is 
  also 
  

   found 
  among 
  the 
  keys. 
  When 
  adult, 
  its 
  food 
  consists 
  largely 
  of 
  

   rabbits," 
  5 
  and 
  sometimes 
  of 
  quails. 
  There 
  is 
  a 
  western 
  diamondback 
  

   which 
  is 
  said 
  to 
  cause 
  twice 
  as 
  many 
  deaths 
  as 
  the 
  eastern 
  species. 
  The 
  

  

  * 
  Ditmars, 
  R. 
  L., 
  Snakes 
  of 
  the 
  world, 
  pp. 
  114-115, 
  1934. 
  

   B 
  Idem, 
  p. 
  113. 
  

  

  