Menopause is a rare phenomenon in the animal world. But that does not mean there are no animals that had. Like humans, killer whales (Orcihus orca) females also lost the ability to reproduce at the end of their natural life.
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| This shows southern resident killer whales in the waters around the San Juan Islands, USA and British Columbia. Both male and female killer whales will remain with their mothers throughout their lives. Adult male killer whales are easily distinguishable from females by their considerably larger dorsal fins. (Picture from: http://www.livescience.com/) |
Stopping the fertile marine mammals may be intended for an elderly parent totally to care for their children until adulthood rather than pregnant again. "Our analysis suggests that male killer whales depend on the parent. They had to fight hard enough to survive without the help of their mother," said Dan Franks, researchers from the University of York, England on September 11, 2012.
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| A killer whale and her calf. (Picture from: http://www.businessinsider.com/) |
An important role of parents in caring for adult children up to explain why the killer whales have developed the post-reproductive longest in the animal kingdom. Individual female killer whales typically stop reproducing at the age of 40 years. Though they can live to be about 90 years old.
In a study published in the journal Science, Franks said the presence of the parent who experienced menopause males actually increase an individual's ability to survive. "But we did not find the same effect on female individuals," he said.
They also found that the mother's death impact the male killer whale. "Children under 30 years old females it is not affected by the death of their mother," kata'Franks. He speculated that the mother of killer whales are more focused on the survival of male children to ensure the maximum growth, so that in time it will deploy calf genes passed on.
"Killer whale is an incredible animal. Their social group really unusual. Mains and their male children are lifelong friends," said Emma Foster, a researcher from the University of Exeter. Foster research shows that killer whales have developed the longest menopause than in non-human species, so as to offer the certainty of survival for the older offspring. *** [LIVESCIENCE | MAHARDIKA SATRIA HADI | KORAN TEMPO 3999]
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