14 February 2009

Mothers' jobs

Two papers on cetacean mothers have been recently published.

One investigated the role of menopause and reproductive senescence in a long-lived social mammal such as killer whales. The study reports that older mothers appear to be better mothers, producing calves with higher survival rates, than younger less-experienced moms.

"Older females may be more successful in raising young because of maternal experience, or they may allocate more effort to their offspring relative to younger females", researchers said.

This result is consistent with similar studies of other mammals; the presence of grandmothers may positively influence survival of juveniles at a critical life stage. The study also confirmed that menopause and long post-reproductive lifespans are not prerogatives of humans.

The other study focused on the whale mothers who teach their babies where to eat. Thanks to genetic and chemical analyses, researchers show that the right whale teach to their calves the location of feeding grounds during a long migration through the South Atlantic Ocean.

Researchers are now linking this result to the ocean present situation and they are raising concern about whales ability to find new places to feed if climate change is disrupting their traditional feeding areas.


Southern Right whale and calf, by Genevieve Johnson (earthOcean)

For more information:
Ward E.J., Parsons K., Holmes E.E., Balcomb K.C., Ford J.K.B. 2009. The role of menopause and reproductive senescence in a long-lived social mammal. Frontiers in Zoology 6: 4. doi:10.1186/1742-9994-6-4

‘Mother whales teach babies where to eat: can Southern right whales adapt if food becomes scarce?’

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