Scientists solve the menopause mystery

Mónica Pérez EDITORIAL USE ONLY

A handout picture provided 23 June 2009 by the Canary Island Cetacean Research (SECAC) shows one of the 14 killer whales (Orcinus orca) which were sighted last week in the Canary Islands' waters, where the presence of this species is infrequent, in Lanzarote, the Canary Islands, southwestern Spain. The biologists took photographs of their dorsal fins, with nearly two meters long, to compare them with the North Atlantic and Strait of Gibraltar killer whale population, where the species is under risk of extinction. The Orcinus orca body can reach 9 meters length in males and 7.7 meters in females. Males reach 5570 kg, as female maximum weight is 3800 kg.

Scientists solve the menopause mystery


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Scientists believe they have resolved a human evolutionary riddle by observing orcas.

The results of the 40-year study were published on Thursday in the Journal of Current Biology.

The comparison between orcas and humans is apparently inevitable from a biological perspective since these are two of only three mammals that experience menopause. Killer whales, like humans, stop reproduction at some point in their lives.

Following orca families in the South Pacific for four decades, scientists now believe to have established that menopause gives children a better chance at survival, preventing “reproductive conflict” between mothers and daughters.

The evolutionary advantage of menopause is that younger females have greater reproductive success than their mothers when breeding at the same time. And their children are more likely to survive. When mothers and daughters co-breed, the mortality hazard of calves from the older generation of females is 1.7 times greater than of calves from younger-generation females.

Female killer whales have evolved the longest post-reproductive lifespan of all non-human animals.

epa05590324 Spanish Lina Alvarez, a 62-year-old mother, poses with her newborn after being discharged from the Lucus Augusti (HULA) University Hospital in Lugo, in the province of Galicia, northwestern Spain, 18 October 2016. According to reports, it is the third child she gave birth to after already giving birth to her second child some ten years after her menopause. EPA/ELISEO TRIGO ATTENTION EDITORS: FACE OF THE BABY PIXELATED BY SOURCE

Spanish Lina Alvarez, a 62-year-old mother, poses with her newborn after being discharged from the Lucus Augusti (HULA) University Hospital in Lugo, in the province of Galicia, northwestern Spain, 18 October 2016. According to reports, it is the third child she gave birth to after already giving birth to her second child some ten years after her menopause. EPA/ELISEO TRIGO ATTENTION EDITORS: FACE OF THE BABY PIXELATED BY SOURCE

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