Table 6 is a summarization of 73 records of individuals that made substantial growth as adults, after they were marked and measured. These records show the slowing trend of growth with advanced age. Also, they show the wide range of individual variation in growth rate, and difference between the sexes. With advanced age, growth in females lags behind that in males to an increasing extent. Exceptionally large individuals, of either sex, are many months old, but some individuals live to be a year old or more without growing much beyond average adult size. The average growth rate of more than 1 mm. per day in young has slowed to less than .1 mm. per day, on the average, in adults exceeding 160 mm., and has slowed to less than .05 mm. per day, on the average, in those exceeding 165 mm. Table 6. Size Groups (Over-all Length) in Recaptured Voles That Were Marked Before Maturity and Therefore Were of Approximately Known Ages. ([M] = Male; [F] = Female) ===============+======================================+============ | Estimated age, in days | Size Group +------------+------------+------------+ Number Length in mm. | Average | Maximum | Minimum | in sample ---------------+------------+------------+------------+------------ 171 to 175 | [M] 435 | ..... | ..... | 1 | [F] 324 | 338 | 310 | 2 | All 361 | 435 | 310 | 3 | | | | 166 to 170 | [M] 304 | 523 | 179 | 9 | [F] 398 | 597 | 158 | 6 | All 346 | 597 | 158 | 15 | | | | 161 to 165 | [M] 227 | 465 | 104 | 15 | [F] 257 | 394 | 134 | 18 | All 243 | 465 | 104 | 33 | | | | 156 to 160 | [M] 188 | 349 | 107 | 12 | [F] 187 | 284 | 93 | 11 | All 188 | 349 | 93 | 23 ---------------+------------+------------+------------+------------ SUMMARY