Definition of estrus in English:


(British estrum, oestrus)


  • A recurring period of sexual receptivity and fertility in many female mammals; heat.

    ‘a mare in estrus’
    • ‘Around 18 hours after giving birth, females experience postpartum estrus, and mate again.’
    • ‘Females have a short estrus period of 3 to 5 days.’
    • ‘However, it is also possible that in years of late snow-melt, pikas may lose litters or reabsorb litters and then breed again in post-partum estrus.’
    • ‘However, if a female's cubs are killed (usually by an intruding male lion), then the female comes into estrus early and has more cubs.’
    • ‘A female may come into her brief period of estrus at any time during the mating season, which runs from late November through mid-January.’
    • ‘Women's sexuality is not limited to a specific period of estrus, as it is in almost all other mammals.’
    • ‘Therefore, if high population density results in increased contact between individuals, this may stimulate ovarian activity and synchronize estrus between females.’
    • ‘In adult females, social rank modulates the length of behavioral estrus, with high ranked females mating for longer periods of time prior to ovulation than lowed rank females.’
    • ‘The estrous cycle is 28 days with a 3 day period of estrus.’
    • ‘Female chipmunks are in estrus for 1 day a year in late April or early May.’
    • ‘However, existing evidence suggests that family breakups, onset of estrus, and breeding opportunities are linked.’
    • ‘Two trials in Texas demonstrated a dramatic drop in pregnancy rates for females displaying estrus during June through September compared with earlier months.’
    • ‘‘When the female is in estrus, breeding bulls that are 35 to 55 years old and in their prime can be many miles away,’ Garstang said.’
    • ‘Fillies began ovulating and advertising estrus by adopting a distinctive posture between one and two years of age.’
    • ‘A beef cow has a 21-day estrous cycle, the period from one estrus, or heat, to the next.’
    • ‘Researchers in Africa have observed that bulls are always looking for mates, using smell and hearing to seek out females in estrus.’
    • ‘Females breed when they are in estrus - a brief period of ovulation that only occurs every two years and lasts just a few days.’
    • ‘The number of males and the number of females in estrus within a 10-mile radius of the male was recorded at each location.’
    • ‘Males mature more slowly; at three, they begin to pester mares in estrus and are driven out of their natal group.’
    • ‘After producing a foal, her periods of estrus are more difficult to detect, and she remains with the father of her offspring.’


Late 17th century: from Greek oistros gadfly or frenzy.