File:Bulletin (1973) (20434015861).jpg

Title: Bulletin
Identifier: bulletin3119731977illi (find matches)
Year: 1918 (1910s)
Authors: Illinois. Natural History Survey Division
Subjects: Natural history; Natural history
Publisher: Urbana, State of Illinois, Dept. of Registration and Education, Natural History Survey Division
Contributing Library: University of Illinois Urbana-Champaign
Digitizing Sponsor: University of Illinois Urbana-Champaign

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July, 1973 Sanderson & Nalbandov: Reproductive Cvcle of the Raccoon 65 uterus of a live female was stimulated, many of the placental sites could best be identified by slight, opaque bumps rather than by the pigmentation. Identification of the location of scars by the presence of bumps was possible for several weeks after parturition, when the uterus was still stimulated, as well as in the stimu- lated uterus at or near estrus. After the uterus regressed, scars were usually read- ily visible as bumps or could be identi- fied by using translucent light to observe the pigmented areas. The pigmented areas could also be located when the uterus was opened or by histological ex- amination. Placental scars seem to persist longer in wild raccoons than they do in captives. The placental scars of captives that we examined from October through January after the births of their litters were gen- erally pale brown, small, and slightly opaque. A majority of the wild females examined during these same months had larger, more opaque scars, often black. Many (55.2 percent in 1959 and 41.0 percent in 1960) uteri of wild, parous females had more than one group of scars, which differed in size and density (Fig. 11 ). Presumably these scars were from difTerent years; however, some might have been from difTerent litters born in 1 year. There was no evidence that as many as 40 or 50 percent of the wild females gave birth to second litters during a single season. Thus, placental scars probably persist for 20 months or longer in many — perhaps in all — wild females. In the few wild females with three groups of scars, the first group may have persisted for as long as 32 months. The placental scars of raccoons are useful for estimating litter size and rate of productivity. However, these scars must be used with caution, and care must be taken to separate properly the groups of scars. We do not know for certain the significance of multiple groups of scars. We can say with reasonable con- fidence that each embryo that reaches 1 month of age is represented by one scar for 10 or more months. Scars in wild females with only one group of scars probably reflect implantation rates for the preceding breeding season. Most single groups of placental scars occur in females that have mated successfully only once. MORPHOLOGY OF THE REPRODUCTIVE TRACTS Males The duct system and accessory glands in the reproductive system of the male raccoon (Fig. 12) are similar to those found in the dog, as described and shown by Nalbandov (1958: 42-44). Seminal vesicles are lacking, as they are in the dog, fo.x (Vulpes fulva), and wolf (Canis lupus). The Cowper's glands (bulbo- urethral glands) are also absent. The walls of the vasa deferentia thicken prior to entering the prostate and form the ampullae. The ampullae and the urethra
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Fig. 11.—Raccoon uterus (X 0.75) split to show two groups of placental scars. This female was killed on January 23. Two light scars were only barely visible in the photogroph but were readily visible in the fresh specimen. Their locations and densities relotive to the three dark scars ore indicated by the light stippling (arrows).

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