“更年期”黑猩猩加深了女性停止生育之秘

The females in a group of wild chimpanzees are the first non-human primates to be documented experiencing menopause（更年期）. The finding， recently published in Science， deepens the mystery of why a handful of mammals — including humans and toothed whales — evolved extended female lifespans beyond their reproductive years.

“There’s so many species who just more or less reproduce until they keel over，” says Tobias Deschner， a primatologist at Osnabrück University in Germany. The riddle， he says， is why a select few buck this trend， ceasing reproduction long before they die.

Researchers followed 185 female members of the Ngogo community of chimpanzees in Kibale National Park， Uganda from 1995 to 2016. The data revealed that， in a pattern similar to that in other chimpanzees and humans， the number of births declined after 30 years old， and ceased altogether by age 50.

Yet， several female chimpanzees continued to live post-reproductive lives， sometimes well into their 60s. Ngogo females spend around one-fifth of their adult lives in this post-reproductive period， roughly half as long as that of hunter-gatherer humans. That number was much larger than the team expected， says Brian Wood， an anthropologist at the University of California， Los Angeles.

The female chimpanzees experience a hormonal（荷尔蒙的） transition similar to that seen in humans. Following post-reproductive Ngogo females to collect samples of urine as it showered from the trees， the scientists found oestrogen and progestin levels falling， paired with follicle-stimulating hormone and luteinizing hormone rising， which control ovulation（排卵） and renewal of the uterine lining after menstruation.

Deschner says that the research highlights the value of long-term observational studies. “The longer such a site exists， the more valuable the data becomes that comes out of that site，” he says. “Just keeping these projects alive is a valuable investment.”

（材料来自Nature网站，有删改）

1. Scientists find from their studies that female chimpanzees ______.

A. have the period of menopause

B. stop giving birth at young age

C. keep reproducing in their life

D. start menopause earlier than whales

2. According to the research， what causes female chimpanzees’ reproductive decline？

A. Natural aging. B. Hormonal fall.

C. Environmental factors. D. Terrible illness.

3. What should scientists do about observational studies according to Deshner ？

A. Stop them if necessary.

B. Just continue their value.

C. Record their existence.

D. Often change the site for them.

4. How does the author support the theme of the text？

A. By giving examples.

B. By stating arguments.

C. By explaining statistical data.

D. By providing research results.

1. A。解析：细节理解题。材料第一段的第一句提到“一群野生黑猩猩中的雌猩猩是第一批被记录到经历更年期的非人灵长类动物”。A项“有更年期”与材料内容相符，故选A。

2. A。解析：细节理解题。材料第三段的第二句提到“数据显示，与其他黑猩猩和人类的情况相似，这些黑猩猩在30岁后生育能力有所下降，到50岁时完全停止生育”。A项“自然老化”与材料内容相符，故选A。

3. B。解析：推理判断题。材料最后一段中提到“Deschner说，这项研究突出了长周期观察研究的价值”“这样一个观察点持续的时间越长，从中得出的数据就越有价值”“光是让这些项目存活下去就是一项有价值的投资”，据此我们可以推断Deschner是想让科学家们把这些项目继续做下去，因为他认为有价值。故选B。

4. D。解析：推理判断题。本题要求判断作者是如何支撑文章的主题的。A项“通过举例”似是而非，材料虽然提到在乌干达做的研究，但这并非简单的举例，而是严谨的实地研究；B项“通过陈述论点”显然不符合材料内容，这篇材料并非仅仅通过论述验证作者的观点，而是有科学实地研究作为支撑；C项“通过解释统计数据”，材料中并未提及；D项“通过提供研究结果”符合实际，材料多处引用科学家的研究结果和实地观察研究结论。故选D。