Scientists have discovered two new species of animals, which have grandmother
MOSCOW, 27 Jun — RIA Novosti. Beluga whales and narwhals were in an elite club of mammals whose females refuse to reproduction and become “grandparents” for the sake of raising the offspring of their daughters. Write about the scientists in an article published in the journal Scientific Reports.
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“We are extremely difficult to understand how there was a modern behavioral instincts of people, as we live in isolation from nature for a very long time. The monitoring of other animal species like these whales, will help us to understand how unusual reproductive strategy “Institute” grandmothers,” said Darren Croft (Darren Croft) from the University of Exeter (UK).
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It is believed that most of the animals retains the ability to reproduce throughout their adult life. Barren elderly individuals are not good for the population, which is why the lifespan of most mammals is limited to the timing of their fertility. There are exceptions to this rule — people, killer whales and dolphins-whales.
At the moment, anthropologists have explained the existence of the elderly the so-called “grandmother hypothesis”. In accordance with this theory, older women cease to breed, for evolutionary reasons — helping their daughters to raise and educate children, grandmother thus increasing the chances of further transmission of their genes. Anthropologists have found confirmation of this theory in populations of Africans stuck in a primitive society.
A year ago, Croft and his colleagues revealed the reason orcas become grandparents — they protect their daughters from unwanted competition within their own “family”, not preventing, and helping to raise grandchildren and great-grandchildren.
“The aging female, in her group there are more and more family members — her children, grandchildren and great grandchildren. This means that if she continues to produce offspring, then they will to compete with her grandchildren and great grandchildren for food, reducing the collective chances that will survive the whole group. Therefore, from an evolutionary point of view, elderly females are more profitable to abandon breeding to teach the young to look for food,” explains Sam Ellis (Sam Ellis), a colleague of the Croft.
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Following this idea, oceanographers have analyzed the structure of the family and behave like the ovaries of other toothed whales. It turned out that three species of these mammals are already known to scientists whales, and belugas and narwhals, also developed “the Institute for grandmothers.”
This is supported by the fact that 35-40 year life full of “blanks” of oocytes in the ovaries of these two types of whales drops to almost zero, significantly faster than the closest relatives. In addition, Beluga whales and narwhals live in large families with a predominance of females and calves that unites them with humans and killer whales, and different from many other whales.
This discovery, according to Croft, strengthens the position of the “grandmother hypothesis” and gives scientists more opportunities to explore the ways that our ancestors could go to a similar way of life in the distant past.
For example, some conclusions can be drawn already now. Ancestors and closest relatives of all three types of whales do not use “Institute for grandmothers”, which means that these animals independently “invented” a similar strategy of survival during their separate evolution. This, in turn, suggests that grandmothers can meet in the animal world, more often than we believe today, conclude the authors.