Wallis Janette, Lemmon W B
Institute for Primate Studies, University of Oklahoma, Norman.
Department of Psychology, University of Oklahoma, Norman.
Am J Primatol. 1986;10(2):171-183. doi: 10.1002/ajp.1350100207.
Previous reports of increased sexual activity associated with genital swelling during chimpanzee pregnancy have suggested that the tumescent pregnant female may be regarded as a regularly cycling estrous female. Analysis of additional data from seven pregnant and eight cycling females, however, indicated that tumescent pregnant females differed from cycling females in some social interactions with males. As in earlier reports, pregnant females were more receptive to male-initiated copulatory bouts. In addition, pregnant females initiated grooming bouts with males much less frequently than did cycling females, and males spent less time grooming and less frequently inspected the genitals of pregnant than cycling cagemates. This tendency to decrease social interaction during pregnancy is consistent with field reports that pregnant chimpanzees prefer the company of their offspring and other noncycling females. In addition, the genital swelling patterns of 40 chimpanzee pregnancies were analyzed. Length of gestation averaged 231.5 days. Although a high degree of individual variation existed, females were swollen an average of 41% of the days observed, yet reached maximum swelling only 8.7% of the time. Genital swelling was less frequent during the third trimester, averaging 50.5, 47.9, and 22.6% tumescent days in each trimester. Young pregnant females showed maximum swelling more often than did older females. This finding is discussed with respect to field reports of intercommunity transfer of young, tumescent female chimpanzees.
先前有关黑猩猩孕期性行为增加与生殖器肿胀相关的报道表明，肿胀的怀孕雌性可能被视为处于规律发情周期的雌性。然而，对来自7只怀孕雌性和8只处于发情周期雌性的更多数据进行分析后发现，肿胀的怀孕雌性在与雄性的一些社交互动方面与处于发情周期的雌性有所不同。与早期报道一致，怀孕雌性对雄性发起的交配行为更易接受。此外，怀孕雌性主动与雄性进行梳理毛发行为的频率远低于处于发情周期的雌性，而且雄性花费在为怀孕雌性梳理毛发上的时间更少，检查其生殖器的频率也低于处于发情周期的同笼伙伴。孕期社交互动减少的这种趋势与野外观察报告相符，即怀孕的黑猩猩更喜欢与自己的后代以及其他非发情周期的雌性待在一起。此外，还对40例黑猩猩怀孕案例的生殖器肿胀模式进行了分析。妊娠期平均为231.5天。尽管个体差异很大，但雌性在观察期内平均有41%的时间生殖器处于肿胀状态，不过只有8.7%的时间达到最大肿胀程度。妊娠晚期生殖器肿胀的频率较低，在每个孕期中，肿胀天数的平均值分别为50.5%、47.9%和22.6%。年轻的怀孕雌性比年长的雌性更常出现最大程度的肿胀。这一发现结合年轻的、生殖器肿胀的雌性黑猩猩在群体间转移的野外观察报告进行了讨论。
