. Bulletin. Natural history; Natural history. September, 1945 Brown & Yeager: Squirrels in Illinois 477 8 7 6 E i 4 O UJ -a TES TES WEIGHT 1 ^>- >3' ⢠NO DATA âOâ0-. A / / If / ft \\ \\ \\ \\ \\ \\ J^"' ⢠.y <^ I I 30 E = 26 22 18 TESTES LENGTH. _l L. _l L. i 24 E \ 16 cr LiJ uJ 8 < 0 ( COWPER'S GLANDS NO DATA "^^ .â cr ^ ^ \ / / / / / / X_ S y^ ^ A ^ â JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC Fig. 9.âBreeding seasons in male squirrels in Illinois, 1940â1942. particularly to the central zone; in the northern and southern zones, the time of corresponding peaks
. Bulletin. Natural history; Natural history. September, 1945 Brown & Yeager: Squirrels in Illinois 477 8 7 6 E i 4 O UJ -a TES TES WEIGHT 1 ^>- >3' ⢠NO DATA âOâ0-. A / / If / ft \\ \\ \\ \\ \\ \\ J^"' ⢠.y <^ I I 30 E = 26 22 18 TESTES LENGTH. _l L. _l L. i 24 E \ 16 cr LiJ uJ 8 < 0 ( COWPER'S GLANDS NO DATA "^^ .â cr ^ ^ \ / / / / / / X_ S y^ ^ A ^ â JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC Fig. 9.âBreeding seasons in male squirrels in Illinois, 1940â1942. particularly to the central zone; in the northern and southern zones, the time of corresponding peaks may, in general, be expected about 6 or 7 days later and earlier, respectively. Duration of the oestrual period, on the basis of evidence at hand, is approximately 10 days. Peak dates for pregnancy and lactation are less easily established, since gestation requires about 45 days and nursing continues for 8 to 10 weeks. Av- erages of all data, tables 15 and 16, indicate that pregnancy peaks in fox squirrels were reached about February 1-15 and July 16â31 ; in gray squirrels, February 10-25 and August 5-20. Lactation peaks in fox squirrels occurred during the months of March and August; in gray squirrels April and September. Considerable overlap was found in the two breeding and young-rearing seasons. Ending the first season was a lactation. 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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Keywords: ., booka, bookcentury1900, bookdecade1910, booksubjectnaturalhistory
