Older killer whales make for more successful mommies
February 3rd, 2009 - 5:26 pm ICT by ANIWashington, Feb 3 (ANI): Older killer whales (Orcinus orca) nearing menopause are more successful in rearing their young, according to a study.
The research has shown that estimated survival rates for calves born to these older mothers were 10 percent higher than those for other calves.
For the research, Eric Ward from the Northwest Fisheries Science Center, Seattle, USA, and colleagues studied killer whales inhabiting the inland and nearshore waters of Washington state (USA) and British Columbia (Canada).
They used a 30-year dataset collected by the Center for Whale Research and Canada’’s Department of Fisheries and Oceans.
“During annual photographic surveys, nearly every individual in the population has been recorded. Each animal has unique pigmentation, scars, and fin shapes, allowing us to track the survival and reproductive performance of each female over time, he said.
The study was aimed to investigate what benefits killer whales derive from the menopause.
One theory, termed the “attentive mother hypothesis”, is that giving birth to calves and then losing the ability to reproduce helps the mother to focus on bringing up her offspring, without wasting time and energy on further pregnancies.
The findings support the theory to an extent in that during a calf’’s first year of life, having a mother who was nearing menopause increased chances of survival.
Ward said: “We found that the oldest mothers may also be the best mothers. 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”.
The study is published in BioMed Central’’s open access journal Frontiers in Zoology. (ANI)
- Oldest killer whales make the best mothers - Feb 03, 2009
- Why killer whales and human females stop breeding early? - Jul 02, 2010
- Humans And Whales Linked By Their "Grandmothers" - Jul 04, 2010
- Killer whales shed new light on human menopause - Jul 02, 2010
- Success in conserving endangered whales depends on understanding feeding behavior - Dec 17, 2009
- Record whale die off baffles experts - Mar 30, 2010
- Several new species of killer whales likely to be found in oceans - Apr 23, 2010
- Mum sperm whales have babysitters when they go food shopping! - Jun 14, 2009
- Babysitting whales look after calves while mums go snacking - Jun 01, 2009
- An Investigation Delves Into Killer Whales And The Inscrutability Of Human Menopause - Jul 04, 2010
- Shed those extra kilos before pregnancy for a healthy baby - Feb 03, 2011
- Whale sharks can produce many offspring from single mating session - Aug 25, 2010
- Record Whale Die-Off Near Argentina Coast - Apr 03, 2010
- Record Whale Calves Die-off Alarms Scientists - Mar 30, 2010
- Frightened birds' wings grow faster and longer - Mar 26, 2011
Tags: biomed central, british columbia canada, department of fisheries, department of fisheries and oceans, eric ward, fin shapes, fisheries and oceans, fisheries science center, killer whales, maternal experience, nearshore waters, northwest fisheries science, northwest fisheries science center, older mothers, photographic surveys, reproductive performance, seattle usa, survival rates, washington state usa, whale research