Scientists decided to study the nature of menopause
To study menopause biologists turned to the dolphins, who have not, and proved that they can develop in older females to better care about the later offspring.
Today we know only four animals, the females which is menopause. Besides humans, this orca, small orca, and dolphins-whales.
The value of this rare evolutionary adaptation remains a mystery, although it is assumed that menopause allows old experienced females to pay attention to the whole herd and other calves, freed from the constant care of their.
This hypothesis of American biologists have decided to check for example other dolphins, common bottlenose dolphins who have menopause does not.
Childhood in bottlenose dolphins are significantly longer than other mammals, maternal care of offspring, on average, four to five years. The typical lifetime of 40-50 years, the first cubs of female bears about 11 years. Kerns Caitlin (Caitlin Karniski) and her colleagues collected and analyzed data on the 34 years of observations 229 females 562 bottlenose dolphins and their calves, which live off the coast of Western Australia.
The article, published in the journal Proceedings of the Royal Society B, scientists have noted that calves born to old females dolphins, rarely reach the age of three years. In addition, the intervals between each subsequent offspring elongate with age females. Less of a chance to grow a new offspring makes females longer and more actively take care of the late cubs: the average duration of this period to old age they have shifted from four to five years, and in some cases – more than eight years.
The authors suggest that such an extended period of caring for kids and the natural decline of the ability of the new offspring are the causes that can lead to the emergence and consolidation of the phenomenon of menopause. Old female it makes sense to invest energy in the care of the offspring than to take a number and expect the next litter.
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