. Bulletin. Natural history; Natural history. July, 1973 Sanderson & Nalbandov: Reproductive Cycle of the Raccoon 39 Table 2.—Testis weights of four raccoons, showing seasonal change Raccoon Estimated Weight of Sperm Number Age Date One Testis Present and Type in Months in Grams or Absent' 1771 (wild) 15 7-18-57 — 20 12-23-57 + 1783 (captive) 15 7-19-57 — 20 12- 6-57 + 1803 (captive) 7 11- 6-57 — 9 1- 3-58 + 2121 (captive) 14 5-23-58 — 17 9- 3-58 — * The plus sign that sperm was present, and the increase in weight occurred from Novem- ber to January (the per
. Bulletin. Natural history; Natural history. July, 1973 Sanderson & Nalbandov: Reproductive Cycle of the Raccoon 39 Table 2.—Testis weights of four raccoons, showing seasonal change Raccoon Estimated Weight of Sperm Number Age Date One Testis Present and Type in Months in Grams or Absent' 1771 (wild) 15 7-18-57 — 20 12-23-57 + 1783 (captive) 15 7-19-57 — 20 12- 6-57 + 1803 (captive) 7 11- 6-57 — 9 1- 3-58 + 2121 (captive) 14 5-23-58 — 17 9- 3-58 — * The plus sign that sperm was present, and the increase in weight occurred from Novem- ber to January (the period of maximum growth rate in juvenile males) in one juvenile male after the removal of one testis in November. After unilateral castration in May the second testis in the remaining adult showed a decrease in weight from May to September, a period when the average weights of testes from wild adults did not differ significantly. Several captive raccoons were ex- amined repeatedly for sperm in their epididymides after they became sexually mature (Fig. 3). From July through October the greatest percentage of adult males were sexually inactive. The histories of several captives show that individual males had periods that aver- aged 3-4 months when they were incap- able of breeding although males with. JAN. FEB. MAR. APR MAY JUNE JULY AUG. SEPT. OCT NOV. Fig. 3.—Percentage of sexually mature captive male raccoons with sperm in the epicJidymi eral at the top of each bar indicates the number of observations for each month. DEC. is. The. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Illinois. Natural History Survey Division. Urbana, State of Illinois, Dept. of Registration and Education, Natural History Survey Division
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