Menopause is when the ovaries stop working, after which ovulation, periods and the production of the hormones oestrogen, progesterone and testosterone ceases, and women can no longer become spontaneously pregnant.
Human women are one of the few species that go through menopause; the only others we know of being female short-toothed whales (belugas, short-finned pilots, orcas and narwhals). Almost all other animals retain the ability to reproduce throughout their lifespan.
Why humans are almost unique in experiencing menopause is not yet fully understood. But, in evolutionary terms, there must be a reason why female humans have developed to stop reproducing and continue to live afterwards.
One theory is the 'grandmother hypothesis', which suggests that older non-reproductive females benefit the group - they can concentrate on seeking food and caring for the babies of younger mothers.
There are also benefits to the individual, including the transition to a stable level of hormones, the ceasing of periods (and the pain and bleeding that goes with them) and no concerns of pregnancy.
この記事は BBC Science Focus の June 2023 版に掲載されています。
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この記事は BBC Science Focus の June 2023 版に掲載されています。
7 日間の Magzter GOLD 無料トライアルを開始して、何千もの厳選されたプレミアム ストーリー、9,000 以上の雑誌や新聞にアクセスしてください。
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