1. Females come into oestrus once a year, probably around December. 2. In British English, the spelling is oestrus or Sstrus. 3. Males kill young to bring the female into oestrus . 4. They were kept apart when Lola came into oestrus . 5. But to an oestrus call males are perfectly silent, " said Langbauer. 6. These groups are led by adult males, depending on the presence of oestrus . 7. Females in oestrus may attract additional males. 8. Eosinophils along with basophils and mast cells, are important mediators of oestrus cycling, allograft rejection and neoplasia. 9. When one of his females comes into oestrus the male concentrates on her and mates with her several times. 10. Menstruation has little social impact among chimpanzees or bonobos, since visible oestrus swellings are the focus of male attention.