
-
Brazil binman finds newborn baby on garbage route
-
US senator smashes record with marathon anti-Trump speech
-
Trump advisor Waltz faces new pressure over Gmail usage
-
Niger junta frees ministers of overthrown government
-
Trump set to unleash 'Liberation Day' tariffs
-
Boeing chief to acknowledge 'serious missteps' at US Senate hearing
-
Real Madrid hold Real Sociedad in eight-goal thriller to reach Copa del Rey final
-
Nuno salutes 'special' Elanga after stunning strike fires Forest
-
PSG survive scare against Dunkerque to reach French Cup final
-
Sundowns edge Esperance as crowd violence mars quarter-final
-
Nottingham Forest beat Man Utd, Saka scores on Arsenal return
-
Elanga wonder-goal sinks Man Utd as Forest eye Champions League berth
-
Stock markets mostly advance ahead of Trump tariffs deadline
-
US movie theaters urge 45-day 'baseline' before films hit streaming
-
Saka scores on return as Arsenal beat Fulham
-
Third-division Bielefeld shock holders Leverkusen in German Cup
-
Ball-blasting 'Torpedo bats' making waves across MLB opening weekend
-
Newsmax shares surge more than 2,000% in days after IPO
-
Thousands of Hungarians protest against Pride ban law
-
GM leads first quarter US auto sales as tariffs loom
-
Tesla sales tumble in Europe in the first quarter
-
No 'eye for an eye' approach to US tariffs: Mexico
-
NFL club owners back dynamic kickoffs, delay tush push vote
-
Trump 'perfecting' new tariffs as nervous world braces
-
Trump nominee says to press UK on Israel arms
-
French court says Le Pen appeal ruling could come before presidential vote
-
The battle to control assets behind Bosnia crisis
-
Prabhsimran powers Punjab to IPL win over Lucknow
-
Mass layoffs targeting 10,000 jobs hit US health agencies
-
Tiger's April Foolishness: plan to play Masters just a joke
-
Myanmar quake toll passes 2,700, nation halts to honour victims
-
Turkish fans, artists urge Muse to cancel Istanbul gig
-
US seeks death penalty for accused killer of insurance CEO
-
UK govt moves to block sentencing guidelines for minority defendants
-
Trump puts world on edge as 'Liberation Day' tariffs loom
-
Swedish journalist jailed in Turkey kept 'isolated': employer
-
Stock markets advance ahead of Trump tariffs deadline
-
Gulf between Everton and Liverpool has never been bigger, says Moyes
-
Finland to withdraw from anti-personnel mine ban treaty
-
UK vows £20 million to boost drone and 'flying taxi' services
-
Ford's US auto sales dip in first quarter as tariffs loom
-
Digging for box office gold, 'A Minecraft Movie' hits cinemas
-
Southampton boss Juric desperate to avoid Premier League 'worst team' tag
-
Thailand rescue dogs double as emotional support
-
Five takeaways from Marine Le Pen verdict
-
Stock markets split ahead of Trump tariffs deadline
-
Turkish fans, artists urge Muse to cancel Istanbul gig over protest dispute
-
Former captain Edwards named new England women's cricket coach
-
Haaland ruled out for up to seven weeks: Man City boss Guardiola
-
UK Supreme Court opens car loans hearing as banks risk huge bill

Mama's boys: Elder orca moms protect sons from fights
A male orca's best friend is his old mother.
That's according to a new scientific paper published Thursday in Current Biology, which found female killer whales that have undergone menopause prevent their sons -- though not their daughters -- from getting injured in fights.
Lead author Charli Grimes told AFP what drew her to the subject was just how rare menopause is in the natural world. Most animals with ovaries remain capable of reproducing until they die, with humans and five species of toothed whales the only known exceptions.
"A big question in our own evolutionary history is, how and why has menopause evolved?" she said.
"In human societies, older females play a role in moderating conflict, and now this latest research has found that that might also be the case in killer whales," added the animal behavior scientist at the University of Exeter.
The study looked at Southern Resident killer whales, which live off the Pacific coast of North America.
These whales live in matriarchal social units -- typically consisting of a grandmother, her male and female offspring, and her daughters' daughters. Female killer whales survive up to 90 years in the wild, and live more than 20 years beyond menopause.
Males will outbreed with females from other pods, but both males and females will stay within the social unit of their birth. Sons remain especially close to their mothers throughout their lives.
- Bite marks -
For their research, Grimes and colleagues examined the accumulation of "tooth rake marks" -- scarring left behind when an orca bites another during rough play or fighting.
"These marks are really great for quantifying social interactions that are otherwise really difficult to observe, since most of the behavior takes place below the surface," she said.
The Center for Whale Research in Washington state has carried out photographic censuses of Southern Resident killer whales since 1976, identifying individuals by their unique dorsal fins and saddle patches.
Orcas have no natural predators, and this subspecies feeds exclusively on salmon, as opposed to prey that can bite back. This means the tooth marks could only be inflicted by their own kind.
By analyzing thousands of photos in a computer program, the team found males who lived with post-reproductive mothers had 35 percent fewer tooth rake injuries compared to males who lived with breeding mothers, and 45 percent fewer than those who lived without their mothers.
It's thought that ceasing breeding frees up time and energy for mothers to protect their sons.
How exactly the post-menopausal moms are helping isn't yet clear, said Grimes. It could be that older females use their knowledge of other pods to steer their sons away from troublemakers.
Or, they could be intervening more directly when a fight is brewing, perhaps using vocalizations to call off their sons. It's not thought that they get involved in fighting themselves, since they have very low rates of scarring.
- Pass the fish -
Daughters, however, were not found to have fewer tooth rakes with their mothers around.
Females are probably less involved in conflict to begin with, said Grimes. Sons moreover breed with multiple females, meaning there is a higher chance of their mother passing on their genes.
Ruth Mace, an anthropologist and biologist at the University College London who was not involved in the study, told AFP that the idea that post-reproductive life had evolved so women can help children is well established in humans.
"So it is very interesting that this is also being established in killer whales," she said.
"It's (a) remarkable study, utilizing an extremely valuable long-term dataset," added Stephanie King, who specializes in dolphin research at the University of Bristol and was also not involved.
Prior work has shown older female orcas share their own fish, pass on ecological knowledge of where and when to find food, and improve their grandchildren's survival rates.
An outstanding question is how exactly they bring about some of these benefits -- something Grimes and her colleagues hope to answer by flying drones over the orcas, documenting what they do under the waves.
O.Norris--AMWN