May 12, 1957 | 790 | 238 | 175 | 32-1/2 September 3, 1957 | 810 | 243 | 208 | 36 October 1, 1958 | 883 | 259 | 206 | 49 July 11, 1959 | 915 | 247[A] | 190 | 58-1/2 September 12, 1960 | 930 | 249[A] | 238 | 72-1/2 September 14, 1961 | 1012 | 268[A] | 332 | 84-1/2 _No. 8, female_ | | | | June 23, 1955 | 601 | 175 | 67 | 22 August 3, 1958 | 920 | 255 | 300[B] | 60 July 23, 1959 | 955 | 281 | 211 | 71 May 18, 1960 | 962 | 262 | 260 | 81 ---------------------+-------------+-------------+--------+---------- [A] Incomplete. [B] With food. [Illustration: Fig. 19. Graph from records of blue racers marked early in life and recaptured, showing average and extreme weights in samples of different ages. Early in life the females outstrip males in growth and the size differential increases throughout life.] A few adult racers recaptured, including different individuals of small, medium, and large size, failed to make any measurable gain in length over periods of months, or even over several years. Most often the large individuals were those that failed to grow or made only slight gains. Some of the snakes that failed to increase in length suffered dramatic weight losses, perhaps as a result of injury, disease, or parasitism. However, other individuals that failed to gain appreciably in length did gain in weight. Doubtless both genetic and environmental factors were involved. A few racers gave the impression of being stunted by adversity. All records obtained of growth (or failure to grow), throughout the period of my study were used in compiling Table 17. Table 16. Growth in Several Racers That Were Already Adult When Originally Captured and That Subsequently Attained Unusually Large Size Column headings: A: Snout-vent length in mm. B: Weight in grams C: Probable age in months