estrus

• Male vampires in Fevre Dream are potent only in the presence of a female in estrus, an event that occurs very infrequently. —  StrangeHorizons,July2002
• Mares which are in the ambivalent early stages of estrus or which are mistakenly in diestrus pose a clear safety threat in close quarters. —  TheHorse.com News
• However, bonobos, [8] dolphins, [9] and chimpanzees are known to engage in sexual intercourse even when the female is not in estrus, the most fertile period of time in the female's reproductive cycle, and to engage in sex acts with same-sex partners. —  Recently Uploaded Slideshows
• Chimps live in a social structure where many males have sex with a female in estrus, so there is an evolutionary advantage to producing gobs and gobs of sperm and being able to deliver large ejaculates. —  Original Signal - Transmitting Digg
• "Normally cycling participants earned about $335 per five-hour shift during estrus, $260 per shift during the luteal phase, and $185 per shift during menstruation," the researchers report. —  Chemical & Engineering News: Latest News

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