Table 12.—Records of Individual Skinks Marked as Young and Recaptured Repeatedly After Attainment of Adult Size, Showing Trend of Progressively Slowing Growth.
| Date | Snout-vent length in mm. | Tail length in mm. | Weight in grams | Remarks | |||
| No. 1. | Male | At an age of 33 months this male was far short of maximum size, and smaller than some males a year younger; all four captures within a 65-foot diameter. | |||||
| April 12, | 1950 | 43 | 71 | 1.5 | |||
| August 30, | 1950 | 56 | 56 + 21 | 5.4 | |||
| May 23, | 1951 | 68 | 59 + 32 | .... | |||
| April 28, | 1952 | 73 | 62 + 38 | 6.6 | |||
| No. 2. | Male | At an age of approximately one year this male was approaching small adult size; when last captured at an age of 34 months, he was a large adult. All five records within a 190-foot diameter. | |||||
| July 5, | 1950 | 61 | 921⁄2 (regenerated) | 5.2 | |||
| July 28, | 1950 | 64 | 97 (regenerated) | 5.4 | |||
| May 3, | 1951 | 68 | 96 (broken stub) | 5.8 | |||
| June 21, | 1951 | 72 | 1011⁄2 (regenerated) | .... | |||
| May 1, | 1952 | 78 | 101 (regenerated) | .... | |||
| No. 3. | Male | This skink was nearly a year old and nearing adult size when first captured; recaptured in each of the four succeeding years, he showed slowing growth. He was near the maximum size at the time of his last capture when he was about 57 months old, and evidently had stopped growing (for movement see [No. 2, p. 110]). | |||||
| June 22, | 1949 | 65 | 111 | .... | |||
| May 4, | 1950 | 72 | 1⁄2 | 115 | 7.3 | ||
| June 17, | 1950 | 73 | 116 | 7.8 | |||
| May 15, | 1951 | 80 | 125 | .... | |||
| May 13, | 1952 | 82 | 125 | .... | |||
| April 6, | 1953 | 82 | 104 (regenerated) | .... | |||
| No. 4. | Female | This individual, marked when less than two weeks old, had grown to nearly the maximum female size at an age of 34 months; all four captures within a 175-foot diameter. | |||||
| July 13, | 1949 | 27 | 341⁄2 | .... | |||
| June 1, | 1950 | 54 | 1⁄2 | 931⁄2 | 3.1 | ||
| August 21, | 1951 | 74 | 119 | .... | |||
| May 1, | 1952 | 76 | 123 | 10.0 | |||
| No. 5. | Female | All six records within a 65-foot diameter (See [Figure 21]). | |||||
| April 15, | 1950 | 43 | 70 | 1.4 | |||
| June 5, | 1950 | 52 | 1⁄2 | 87 | 2.8 | ||
| May 25, | 1951 | 71 | 82 + 29 | .... | |||
| September 28, | 1951 | 73 | 111 (regenerated) | .... | |||
| April 26, | 1952 | 74 | 113 (regenerated) | 7.4 | |||
| April 24, | 1953 | 76 | 114 (regenerated) | .... | |||
| No. 6. | Female | Hatched in July 1949, this skink had attained the maximum female size at an age of a little more than three years; (for movement see [Figure 25]). | |||||
| April 21, | 1950 | 46 | 75 | 2.1 | |||
| May 7, | 1950 | 48 | 15 (broken stub) | 2.0 | |||
| May 3, | 1951 | 74 | 29 + 57 | 8.5 | |||
| May 2, | 1952 | 78 | 25 + 64 | .... | |||
| August 27, | 1952 | 79 | 1⁄2 | 95 (regenerated) | 8.3 | ||
| No. 7. | Female | Hatched in July 1949, this skink was 11 months old and about half-grown when it was marked. When last caught at an age of 35 months it was of average adult female size, having grown less than numbers 4 and 6 at the same age. All five captures were within a 60-foot diameter ([Fig. 24]). | |||||
| June 5, | 1950 | 51 | 82 | 2.5 | |||
| July 13, | 1950 | 59 | 93 | 3.9 | |||
| July 29, | 1950 | 64 | 98 | 4.4 | |||
| August 21, | 1951 | 69 | 80 (broken stub) | 5.0 | |||
| May 28, | 1952 | 73 | 83 + 91⁄2 | .... | |||
| No. 8. | Female | Hatched in July 1949, this skink was of average adult female size and was breeding in May 1951; it grew nearly to maximum female size in the next 11 months. All captures | |||||
| April 26, | 1950 | 50 | 1⁄2 | 781⁄2 | 2.7 | ||
| May 24, | 1951 | 74 | 107 (regenerated) | .... | |||
| April 28, | 1952 | 78 | 93 (regenerated) | 8.5 | |||
| April 23, | 1953 | 80 | 93 (regenerated) | .... | |||
| No. 9. | Female | All three captures at the same site. | |||||
| July 5, | 1950 | 60 | 95 | 4.5 | |||
| August 6, | 1951 | 71 | 1061⁄2 | 5.6 | |||
| May 28, | 1952 | 72 | 110 | 8.5 | |||
| No. 10. | Male | Hatched in July 1949, this male grew less rapidly than most, and in the spring of 1953 was smaller than some others that were a year younger, or even two | |||||
| April 23, | 1950 | 46 | 1⁄2 | 66 (regenerated) | 1.8 | ||
| June 13, | 1950 | 52 | 1⁄2 | 26 + 3 | 2.7 | ||
| September 2, | 1950 | 66 | 32 + 51 | 6.2 | |||
| May 29, | 1951 | 67 | 33 + 58 | .... | |||
| August 3, | 1951 | 70 | 94 (regenerated) | .... | |||
| March 27, | 1953 | 74 | 78 (regenerated) | 7.1 | |||
| No. 11. | Female | This skink had attained maximum female size when she was a little less than four years old. | |||||
| April 26, | 1950 | 50 | 1⁄2 | 781⁄2 | 2.7 | ||
| May 24, | 1951 | 74 | 87 | .... | |||
| April 28, | 1952 | 78 | 72 + 21 | 8.5 | |||
| April 23, | 1953 | 80 | 73 + 20 | .... | |||
Differences in their growth rates therefore reflect differences in sex, individual vigor, and local situation, in individuals living at the same time and within the same general environment.
Changing weather, and other factors that vary from year to year cause marked differences in the dates of important events in the annual cycle, and in the stage of development at any given date. Data are available for five successive annual broods of young, those of 1948, 1949, 1950, 1951, and 1952, and each brood differs from the others to some extent, as shown in Figures [11] to [13]. In 1949, for instance, young hatched relatively early, and probably most of them were active by the middle of July. They made rapid growth in August, averaging larger than young hatched in other years on any given date in late summer. However, they retired into dormancy early in the fall. Cool and dry weather in early September ended their activity for the season. In 1950, young hatched, on the average, at least three weeks later, about the first of August, but they remained active until late in September, and by hibernation time had partly caught up to the stage of development attained by the young of 1949. Most young of 1951 hatched late in the first half of August, and at first were smaller than those of 1950 and much smaller than those of 1949 on corresponding dates, but favorable weather in the early fall hastened their development. By early September they had caught up and passed the stage of development of young of 1950 and by the time they retired to dormancy in late September, they had reduced by half the size-advantage of the young of 1949 at the time these latter retired into hibernation. The young of 1951 appeared to be few in numbers, and a lack of competition may have been a factor in their rapid early development.
Fig. 15. Records of growth in another group of recaptured young that grew less rapidly than those of [Fig. 14].
The young of 1948, first sampled after their emergence from their first hibernation in mid-April of 1949, were then somewhat intermediate in size as compared with those of 1949 and 1950 at the same times of year. Their subsequent development was rapid; by late May they had caught up and passed the stage reached by the 1949 young at the same time of year. The young of 1950 after having a late start, were further set back by cold weather in April 1951 delaying their emergence from hibernation. As a result they were still unusually small in late April and May. Even though they grew rapidly subsequently, they were consistently smaller than those of other broods on corresponding dates. Favorable fall weather prolonging the 1951 growing season into late September beyond the time of retirement in other years may have permitted many of them to attain adult size.