Adult killer whales still rely on their mothers

Well-known is the most aggressive fish on the ocean, but killer whales are actually their mother's good children, a study in Science magazine said.

Scientists found the longest menopausal killer whale among the animals except humans. This helps them to nurture the grown-up sons, increasing the ability to transmit seeds to the next generation.

Female killer whales often stop breeding at age 30 or 40, but they live up to 90 years old. The reason why this fish has so long menopause is still a mystery.

Scientists now believe that male killer whales often live with their mothers for a long time.

British and Canadian scientists analyzed 36-year studies of killer whales in the North Pacific. They found that the duration of the whale's life after menopause greatly affected the life of the cub.

For male whales over the age of 30, the death of a whale increases its risk of death by 14 times. Female whales often live with their mothers, but are less dependent. A 30-year-old female whale is also three times more likely to die after a mother's whale dies.

Dr. Dan Franks, of the Department of Biology at York University, said: ' Our analysis shows that male whales often live with their mothers and face many difficulties to survive without their mothers. The demand for child care explains why whales have the longest menopause in animals. '

It is suggested that to increase the likelihood of propagation for later generations, mother whales often focus on taking care of male whales.

The co-author, Dr. Darren Croft, of the University of Exeter, said: 'Both humans and whales have a very special prolonged menopause. Although this feature is common, the benefits from this are different for each species. This reflects the social structure of different humans and whales'.

Dailymail said that menopause is partly to help women focus on taking care of their grandchildren. While in killer whales, they mainly feed their children and are mostly males.