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Mating

Mating Behaviors

Males can ejaculate multiple times in a row, and this increases the likelihood of pregnancy as well as decreases the number of stillborns. Multiple ejaculation also means that males can mate with multiple females, and they exhibit more ejaculatory series when there are several oestrus females present. Males also copulate at shorter intervals than females. In group mating, females often switch partners.

Dominant males have higher mating success and also provide females with more ejaculate, and females are more likely to use the sperm of dominant males for fertilization.

In mating, female rats show a clear mating preference for unknown males versus males that they have already mated with (also known as the Coolidge effect), and will often resume copulatory behavior when introduced to a novel sexual partner.

Females also prefer to mate with males who have not experienced social stress during adolescence, and can determine which males were stressed even without any observed difference in sexual performance of males experiencing stress during adolescence and not.

Reproduction

Females are capable of becoming pregnant immediately after giving birth, and can nurse one litter while pregnant with another. Females are able to produce and raise two healthy litters of normal size and weight without significantly changing their own food intake. However, when food is restricted, females can extend pregnancy by over two weeks, and give birth to litters of normal number and weight.

References

1. Galef BG, Lim TCW, Gilbert GS. 2008. Evidence of mate choice copying in Norway rats, Rattus norvegicus. Animal Behavior Vol 75 (3) 1117-1123
2. McClintock MK, Anisko JJ, Adler NT. 1982. Group mating among Norway rats II. The social dynamics of copulation: Competition, cooperation, and mate choice. Animal Behavior Vol. 30 (2) 410-425.
3. McClintock MK, Anisko JJ. 1982. Group mating among Norway rats I. Sex differences in the pattern and neuroendocrine consequences of copulation. Animal Behavior 30 (2) 398-409
4. Ventura-Aquino E, Banos-Araujo J, Fernandez-Gausti A, Parades RG. 2016. An unknown male increases sexual incentive motivation and partner preference: Further evidence for the Coolidge effect in female rats. Physiology & Behavior 158: 54-59.
5. Davis HN, Connor JR. 1980. Brief report: Male modulation of female reproductive physiology in Norway rats: effects of mating during postpartum estrus. Behavioral and Neural Biology 29(1): 128-131
6. Miller N. 1911. Reproduction in the Brown Rat (Mus Norwegicus). The American Naturalist. 45 (538): 623-635.
7. Brooks JE, Bowerman AM. 1971. Estrogenic Steroid Used to Inhibit Reproduction in Wild Norway Rats. The Journal of Wildlife Management. 35 (3) 444-449.
8. Woodside B, Wilson R, Chee P, Leon M. 1981. Resource Partitioning during Reproduction in the Norway Rat. The American Association for the Advancement of Science. 211 (4477) 76-77.
9. McCormick CM, Cameron NM, Thompson MA, Cumming MJ, Hodges TE, Langett M. 2017. The sexual preference of female rats is influenced by males' adolescent social stress history and social status. Hormones and Behavior. 89: 30-37.
10. Gilbert AN, Rosenwasser AM, Adler NT. 1985. Timing of parturition and postpartum mating in norway rats: Interaction of an interval timer and a circadian gate. Physiology & Behavior. 34 (1): 61-63.

from Kasey: looks like you have a great set of information that you understand well. My biggest suggestion right now would be to come up with more of an evolutionary framework for your article, and try and place all of the information in some sort of story line so that the paragraphs inform each other. More comments later after you finish your article summary!Evol&Glass (talk)