U. William Huck

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Female promiscuity can lead to the spermatazoa of several males 'competing' to fertilize the ova of a single female. Such promiscuity is relatively common among mammals and has resulted in a suite of adaptations associated with sperm competition. In the last decade, laboratory scientists using experimental techniques have clarified the physiological and(More)
Levels of circulating progesterone (P) were significantly reduced in socially subordinate female golden hamsters following brief exposures to another female. Reduced P levels were accompanied by an increased incidence of implantation failure when social interactions occurred on days 2-4 after mating and by increased fetal mortality when interactions(More)
Pairs of female hamsters were acclimated to seminatural enclosures and permitted to interact for brief periods on days 12-14 of gestation or on days 2-4 of lactation. In one experimental paradigm, food was provided in excess of the daily requirements while in a second, food rations were restricted. Control females were similarly housed and fed but were not(More)
Early postweaning experience in an enriched environment had a greater influence on the open-field behavior and body weight of wild Norway rats than of their domestic counterparts. Genetic changes accompanying the domestication process may have reduced the relative impact of postweaning experience on the development of the domestic rat's response to changes(More)
Recently mated female golden hamsters (Mesocricetus auratus) were paired with 12-day pregnant animals for three 10-min periods on 3 consecutive days. Pregnancy success was significantly reduced among subordinate recently mated females whereas litter size was significantly reduced among subordinate 12-day pregnant females. Additional results indicated that(More)
Female golden hamsters (Mesocricetus auratus) which have actively terminated mating with one male will respond in succession to two or more novel males. However, mating with the first male results in a reduction in receptivity shown toward a second male, with the size of the decrease being proportional to the amount of copulatory stimuli provided by the(More)
When tested in a Y-maze olfactometer, male brown and collared lemmings (Lemmus sibiricus = trimucronatus and Dicrostonyx groenlandicus) preferred the odor of unmated receptive females to the odor of females with which they had just copulated. Similarly, sexually satiated males preferred the odor of an unmated receptive female to that of a strange female(More)
Bruce (1960) first demonstrated that the presence of a strange male mouse blocked the pregnancy of recently impregnated females in the laboratory. Pregnancy blockage was followed by a return to oestrus 4-5 days after the original mating, and fertile mating with the second male typically occurred. Subsequent investigations of the generality of the 'Bruce(More)
The climbing behaviour of wild and domestic Norway rats (Rattus norvegicus) was compared after early rearing in three post-weaning environments offering different climbing experiences. Wild rats climbed in the test apparatus even when denied early climbing experience; male domestic rats did not. Early climbing experience increased the climbing scores of(More)