How grandmothers help young killer whales survive


This December 2018 video says about itself:

Inside the killer whale matriarchy – Darren Croft

Pods of killer whales inhabit the waters of every major ocean on Earth. Each family is able to survive thanks mainly to one member, its most knowledgeable hunter: the grandmother. These matriarchs can live 80 years or more and their expertise can mean the difference between life and death for their families. Darren Croft details the lives of killer whales and the dangers facing their survival.

Read more here.

From the University of York in England:

Killer whale grandmothers boost survival of calves

Post-menopausal killer whale grandmothers improve the chances of survival for their grand-calves

December 9, 2019

Post-menopausal killer whale grandmothers improve the chances of survival for their grand-calves, new research has found.

The study found that grandmothers who were no longer able to reproduce had the biggest beneficial impact on the survival chances of their grand-offspring. This may be because grandmothers without calves of their own are free to focus time and resources on the latest generation, the researchers suggest.

The research team also found that grandmothers had a particularly important role in times of food scarcity, as the impact on a calf of losing a post-menopausal grandmother was highest in years when salmon was scarce.

Previous research has shown that post-reproductive female killer whales are the most knowledgeable and provide an important leadership role for the group when foraging in salmon grounds.

These benefits to the group may help to solve the long-standing mystery of why the menopause has evolved in some species of whales and in humans, the authors of the study say.

Senior author of the study, Dr Dan Franks from the Department of Biology, at the University of York, said: “The study suggests that breeding grandmothers are not able to provide the same level of support as grandmothers who no longer breed. This means that the evolution of menopause has increased a grandmother’s capacity to help her grand-offspring.

“The death of a post-menopausal grandmother can have important repercussions for her family group, and this could prove to be an important consideration when assessing the future of these populations. As salmon populations continue to decline, grandmothers are likely to become even more important in these killer whale populations.”

The study involved an international research team from the Universities of York and Exeter (UK), the Centre for Whale Research (USA) and Fisheries and Oceans Canada.

The scientists analysed 36 years of data gathered by the Center for Whale Research and Fisheries and Oceans Canada on two populations of resident killer whales. The populations (which include several pods, made up of multiple family groups) live off the North West Pacific Coast of Canada and the US and feed on Chinook salmon.

In resident killer whales, both sons and daughters stay with their mothers for life, but they mate with individuals from a different family group. Male killer whales typically have a shorter lifespan than females with many not surviving beyond 30 years. Females usually stop reproducing in their 30s-40s, but just like humans they can live for many decades following menopause.

Lead author, Dr Stuart Nattrass, from the University of York, added: “The findings help to explain factors that are driving the whales’ survival and reproductive success, which is essential information given that the Southern Resident killer whales — one of the whale populations under study — is listed as endangered and at risk of extinction.

“We suspect when breeding grandmothers are supporting their own calves, their movement and activity patterns are constrained and they are not able to provide support and leadership in the same way as post-menopausal females. Also, grandmothers with their own calves will be busy caring for their own calves, and be able to invest less in their grand-offspring, compared to post-menopausal grandmothers.

We are currently conducting observational studies with drones to directly study helping behaviour between family members in these killer whales.”

Co-author of the study, Prof Darren Croft from the University of Exeter, said “The menopause has only evolved in humans, killer whales and three other species of toothed whales and understanding why females of these species stop reproduction well before the end of life is a long-standing evolutionary puzzle.

“Our new findings show that just as in humans, grandmothers that have gone through menopause are better able to help their grand offspring and these benefits to the family group can help explain why menopause has evolved in killer whales just as it has in humans.”

Orcas in Norway, video


This 9 August 2018 video says about itself:

Orcas Co-Exist With Norway’s Arctic Fishermen

From The Shadows: The symbiotic relationship between Atlantic orcas and the fishermen of Norway is unique. Following this story, underwater photographer Jacques de Vos captures the first footage of the whales feeding at night.

In Northern Norway herring abounds, attracting orcas in their hundreds. Having learnt that escaped herring from the fishermen’s nets are easy prey, the whales can hear the fishing boats pumping their catch from as far as 18km away.

“Sometimes it’s kind of like we help each other”, says professional fisherman Borre Hansen, as orcas circle around his boat. Ensuring that no orcas are captured in his nets “is the biggest challenge” he faces. Filming these animals for the first time at night, Jacques is able to capture their secretive underwater world, noticing their playful and inquisitive behaviour. “This was as much a social ‘get together’ as it was about the feeding”, he marvels.

Ice-trapped orcas saved in Russia


This video from Russia says about itself:

19 April 2016

After an eight-hour-long operation rescuers freed three orcas, including one pup, which had got trapped in ice in the Sea of Okhotsk, Sakhalin, on Tuesday.

1,000 dolphins flee killer whales, video


This video from California in the USA says about itself:

Killer Whales Ambush A Pod of 1,000 Dolphins

14 April 2016

This was an incredible encounter. I just happened to be in the right spot at the right time. It’s very rare that everything comes together and we’re able to document these types of encounters. We know it happens regularly with the common dolphins. But there’s rarely someone there with their video camera focused and waiting for it to happen. Incredible morning on The Monterey Bay for me.

1970s killer whale still alive


This video from the USA says about itself:

29 April 2013

A couple vacationing in Mexico encountered a number of killer whales swimming alongside their boat during a trip.

From the BBC, with video there:

1970s killer whale Dopey Dick spotted off Scotland

3 hours ago

Scientists studying Scotland’s killer whales have made a remarkable discovery.

They have identified a whale which hit the headlines in the 1970s after swimming up the River Foyle in Northern Ireland.

Back then, he was dubbed “Dopey Dick”.

Today, he’s known as Comet… and is still believed to be alive and well.

BBC Scotland‘s environment correspondent, David Miller, reports.

Orcas in the North Sea, video


This video says about itself:

11 October 2015

Ship in North Sea surrounded by Killer Whales.

Older female killer whales become pod leaders


This 2014 video says about itself:

In this intriguing talk, Scott Gass discusses the social structure of killer whales and their superb communication skills when it comes to hunting and protecting their young. Their brand of teamwork is tremendously applicable beyond the ocean.

From the Los Angeles Times in the USA:

Menopausal whales lead the group, study says

By Melissa Healy

Sharelines

Mystery solved (maybe): Some females live beyond their reproductive years because their wisdom benefits kin

Menopause: an evolutionary mystery unique to humans, killer whales and short-finned pilot whales

Female killer whales can live past 90. Males rarely survive after 50

What does an ocean-going titaness do after she has the lost the ability to bear young?

Well, for starters, she goes on living–sometimes past the ripe old age of 90, while male killer whales over 50 are dying off in droves. Throughout the animal kingdom, that is unusual enough.

But the menopausal female killer whale does more than survive, says a new study: She “leans in,” becoming an influential leader of younger killer whales, honing the survival skills of her progeny–and their progeny–unencumbered by direct childcare duties of her own.

Quite the opposite of being a burden to her kind, her post-menopausal leadership role seems to make the older female killer whale her species’ evolutionary ace in the hole.

Published in the journal Current Biology, the new research finds that among killer whales, females beyond their reproductive years become habitual leaders of collective movement–generally foraging movement–within their pods. Their position “on point” becomes particularly prominent in lean years, when salmon–the mainstay of the killer whales’ diet–is scarce.

The new findings offer the first evidence that in certain species and under specific circumstances, females who live well beyond their reproductive years “act as repositories of ecological knowledge.”

That helps solve an enduring mystery among biologists: Why–in humans and in two species of toothed whales only–would individuals who no longer propagate their genes continue to survive?

The authors of the study are marine mammal researchers from the universities of York and Exeter in Great Britain and the Center for Whale Research in Washington state. To glean their findings, they analyzed 751 hours of video taken of Southern resident killer whales during annual salmon migrations off the coast of British Columbia and Washington.

The videos were taken over a period of nine years. They captured the movements of pods of killer whales whose populations have been identified and tracked since 1976. That allowed the researchers to determine the age and relatedness of the 102 creatures whose movements they analyzed.

Such detail also allowed the authors to speculate on why post-menopausal survival is so very rare. If post-reproductive females can be such an evolutionary boon for their kin, why do they not survive to serve that function across many species?

Some have suggested that for humans, at least, the post-menopausal survival of women is merely an artifact of better medical care.

Not so, new research–including the killer whales study–suggests. The answer, the authors of this study wrote, may lie in different kinship patterns. Among killer whales, generations of males and females stay together throughout their lives, foraging as a group. As a female ages, her level of genetic relatedness to members of her pod increases.

“Menopause will only evolve,” they wrote, “when inclusive fitness benefits outweigh the costs of terminating reproduction.”

In short, an older female’s continued value to the group may be a function not only of her accumulated knowledge about the whereabouts of food, shelter and predators, but also of her genetic stake in the group’s survival.

That was the case, too, in hunter-gatherer human societies, the authors note. As human societies evolved, women reaching sexual maturity tended to leave the group. As her sons and their many mates and children populated her group, an aging woman’s “relatedness” to that group tended to grow.

In contrast, among other long-lived mammals, sons move off as they reach sexual maturity. So a female becomes less related to the “pod” she stays with as she become older. Under those circumstances, the authors write, she may have sufficient ecological wisdom but not a sufficient level of “relatedness” to her group to ensure her survival beyond the years of reproduction.