It is thought that the female sex hormone oestrogen - produced at higher rates during a woman's reproductive life - raises the risk of these diseases. 据说女性在生殖周期内分泌更多雌性激素使得她们更易于染上这些疾病。
Hormone analysis showed that the calling behaviour of copulating females was unrelated to their fertile period and likelihood of conception. 因此，嚎春可能是雌猩猩用以向高级别雄性展示自己的有效策略，在混淆其配偶的真实身份后，利于其在以后获得源自这些高阶层人物的支持。
