General, Research, Technology

People are not the only species that grandmothers help to raise offspring

It is known that in the animal kingdom - among dozensthousand mammals, birds, fish and amphibians - only a few individuals reach adulthood. Moreover, after the loss of the ability to bear offspring (menopause), not all females survive. However, according to a study published in PNAS, menopause has its own advantages and not only people use them. So, cetaceans, including belugas, narwhals and killer whales are attracted to help in raising offspring of grandmothers. It turned out that menopause seriously increases the chances of survival of the younger generation.

It turned out that killer whale grandmothers help parents raise offspring

Another confirmation of the “grandmother's hypothesis”

Studying Orca Population Data in the StateWashington in the United States and British Columbia in Canada, researchers found that the mortality rate of newborn babies increased immediately after the death of their grandmother, compared with the babies whose grandmothers were alive. The study suggests that mature killer whales that do not breed increase their chances of survival. Scientists have concluded that the life of a grandmother after menopause is important for her family group. Moreover, the results of the study may be an important factor in assessing the future populations of these mammals. Note that today the population of killer whales continues to decline, so researchers believe that the role of grandmothers is likely to become even more important. Orca females reach puberty at about 10 years old and cease to breed at the age of 30 to 40 years. Moreover, in the wild, they can live much longer: from 80 to more than 100 years.

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The results of previous studies have shown thata limited reproductive period entails less competition for food for offspring. It turned out that killer whale grandmothers are perceived as leaders. Moreover, they know better hunting grounds and equipment.

Killer whales demonstrated the benefits of menopause

These benefits can be explained by the “hypothesisgrandmothers ”, which suggests that menopause creates a generation of wiser family members, which contributes to the overall well-being of their relatives. Nevertheless, researchers believe that not everything is so simple, since other animals, such as elephants, also have grandmothers who take care of their grandchildren. However, they do this for their own children as well.

During the study, the team found that inDuring the two years after the maternal grandmother died, the probability of young killer whales to die was 4.5 times higher than that of killer whales with live grandmothers in postmenopause, and 1.5 times higher than that of killer whales, whose grandmothers were of reproductive age.

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Scientists believe that when grandmothers supporttheir own children, their movements and the nature of their activities are limited, and they are not able to provide support just like killer whales in postmenopause. Probably, menopause developed in killer whales for precisely these reasons. To better understand the relationships between different generations of killer whales, scientists intend to use drones in the future.