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Elephant seals sleep for just two hours a day, deep dive research reveals

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Seals dozing on the beach may appear to be enjoying the ultimate life of leisure. However, groundbreaking research has revealed that for most of their lives elephant seals sleep just two hours daily in a series of short naps while performing deep dives.

The findings, revealed in the first study to record brain activity in a free-ranging, wild marine mammal, show that during the months they spend at sea, elephant seals rival the record for the least sleep among all mammals, currently held by African elephants. The seals were found to typically sleep in 10-minute bursts during deep, 30-minute dives, often spiralling downwards while dreaming, and occasionally lying down for a nap on the seafloor.

“For years, one of the central questions about elephant seals has been when do they sleep,” said Prof Daniel Costa, a marine ecologist at the University of California Santa Cruz and senior author. “We thought they must be sleeping during what we call drift dives, when they stop swimming and slowly sink, but we really didn’t know.”

Costa’s lab has been tracking elephant seals at the Año Nuevo reserve for more than 25 years, using increasingly sophisticated tags to track the movements and diving behaviour of the seals during their foraging migrations, when they head out into the north Pacific Ocean for as long as eight months.

“Now we’re finally able to say they’re definitely sleeping during those dives, and we also found that they’re not sleeping very much overall compared to other mammals,” Costa added.

The scientists believe that sleeping while diving allows the seals to avoid predation: they are most vulnerable to predators, including sharks and killer whales, while at the ocean surface, so they only spend a few minutes there to breath between dives.

“They’re able to hold their breath for a long time, so they can go into a deep slumber on these dives deep below the surface where it’s safe,” said Jessica Kendall-Bar, the paper’s first author, who developed the system as a graduate student at UC Santa Cruz and who now works at UC San Diego.

In the latest study, 13 young female seals were fitted with a neoprene headcap to secure sensors on the head that could reliably record brain waves in a scan known as an electroencephalogram or EEG. Time-depth recorders, accelerometers, and other instruments were also used to track the seals’ movements.

“I spent a lot of time watching sleeping seals,” Kendall-Bar said. “Our team monitored instrumented seals to make sure they were able to reintegrate with the colony and were behaving naturally.”

The recordings, collected from the seals during more than 100 dives, revealed that as they descended, seals entered a deep sleep stage known as slow-wave sleep while maintaining a controlled glide downward and then entered rapid-eye-movement (REM) sleep, when sleep paralysis causes them to turn upside down and drift downwards in a “sleep spiral”.

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At the depths at which this happens, the seals are usually negatively buoyant and continue to fall passively in a corkscrew spiral like a falling leaf. In shallower waters over the continental shelf, elephant seals sometimes sleep while resting on the seafloor.

“They go into slow-wave sleep and maintain their body posture for several minutes before they transition into REM sleep, when they lose postural control and turn upside down,” Kendall-Bar said.

The team now plans to use similar methods to study brain activity in other species of seals, sea lions and also human free divers.

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The body of a Ugandan Olympic athlete who was set on fire by her partner is received by family

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NAIROBI, Kenya (AP) — The body of Ugandan Olympic athlete Rebecca Cheptegei — who died after being set on fire by her partner in Kenya — was received Friday by family and anti-femicide crusaders, ahead of her burial a day later.

Cheptegei’s family met with dozens of activists Friday who had marched to the Moi Teaching and Referral Hospital’s morgue in the western city of Eldoret while chanting anti-femicide slogans.

She is the fourth female athlete to have been killed by her partner in Kenya in yet another case of gender-based violence in recent years.

Viola Cheptoo, the founder of Tirop Angels – an organization that was formed in honor of athlete Agnes Tirop, who was stabbed to death in 2021, said stakeholders need to ensure this is the last death of an athlete due to gender-based violence.

“We are here to say that enough is enough, we are tired of burying our sisters due to GBV,” she said.

It was a somber mood at the morgue as athletes and family members viewed Cheptegei’s body which sustained 80% of burns after she was doused with gasoline by her partner Dickson Ndiema. Ndiema sustained 30% burns on his body and later succumbed.

Ndiema and Cheptegei were said to have quarreled over a piece of land that the athlete bought in Kenya, according to a report filed by the local chief.

Cheptegei competed in the women’s marathon at the Paris Olympics less than a month before the attack. She finished in 44th place.

Cheptegei’s father, Joseph, said that the body will make a brief stop at their home in the Endebess area before proceeding to Bukwo in eastern Uganda for a night vigil and burial on Saturday.

“We are in the final part of giving my daughter the last respect,” a visibly distraught Joseph said.

He told reporters last week that Ndiema was stalking and threatening Cheptegei and the family had informed police.

Kenya’s high rates of violence against women have prompted marches by ordinary citizens in towns and cities this year.

Four in 10 women or an estimated 41% of dating or married Kenyan women have experienced physical or sexual violence perpetrated by their current or most recent partner, according to the Kenya Demographic and Health Survey 2022.

The Canadian Press. All rights reserved.

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The ancient jar smashed by a 4-year-old is back on display at an Israeli museum after repair

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TEL AVIV, Israel (AP) — A rare Bronze-Era jar accidentally smashed by a 4-year-old visiting a museum was back on display Wednesday after restoration experts were able to carefully piece the artifact back together.

Last month, a family from northern Israel was visiting the museum when their youngest son tipped over the jar, which smashed into pieces.

Alex Geller, the boy’s father, said his son — the youngest of three — is exceptionally curious, and that the moment he heard the crash, “please let that not be my child” was the first thought that raced through his head.

The jar has been on display at the Hecht Museum in Haifa for 35 years. It was one of the only containers of its size and from that period still complete when it was discovered.

The Bronze Age jar is one of many artifacts exhibited out in the open, part of the Hecht Museum’s vision of letting visitors explore history without glass barriers, said Inbal Rivlin, the director of the museum, which is associated with Haifa University in northern Israel.

It was likely used to hold wine or oil, and dates back to between 2200 and 1500 B.C.

Rivlin and the museum decided to turn the moment, which captured international attention, into a teaching moment, inviting the Geller family back for a special visit and hands-on activity to illustrate the restoration process.

Rivlin added that the incident provided a welcome distraction from the ongoing war in Gaza. “Well, he’s just a kid. So I think that somehow it touches the heart of the people in Israel and around the world,“ said Rivlin.

Roee Shafir, a restoration expert at the museum, said the repairs would be fairly simple, as the pieces were from a single, complete jar. Archaeologists often face the more daunting task of sifting through piles of shards from multiple objects and trying to piece them together.

Experts used 3D technology, hi-resolution videos, and special glue to painstakingly reconstruct the large jar.

Less than two weeks after it broke, the jar went back on display at the museum. The gluing process left small hairline cracks, and a few pieces are missing, but the jar’s impressive size remains.

The only noticeable difference in the exhibit was a new sign reading “please don’t touch.”

The Canadian Press. All rights reserved.

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B.C. sets up a panel on bear deaths, will review conservation officer training

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VICTORIA – The British Columbia government is partnering with a bear welfare group to reduce the number of bears being euthanized in the province.

Nicholas Scapillati, executive director of Grizzly Bear Foundation, said Monday that it comes after months-long discussions with the province on how to protect bears, with the goal to give the animals a “better and second chance at life in the wild.”

Scapillati said what’s exciting about the project is that the government is open to working with outside experts and the public.

“So, they’ll be working through Indigenous knowledge and scientific understanding, bringing in the latest techniques and training expertise from leading experts,” he said in an interview.

B.C. government data show conservation officers destroyed 603 black bears and 23 grizzly bears in 2023, while 154 black bears were killed by officers in the first six months of this year.

Scapillati said the group will publish a report with recommendations by next spring, while an independent oversight committee will be set up to review all bear encounters with conservation officers to provide advice to the government.

Environment Minister George Heyman said in a statement that they are looking for new ways to ensure conservation officers “have the trust of the communities they serve,” and the panel will make recommendations to enhance officer training and improve policies.

Lesley Fox, with the wildlife protection group The Fur-Bearers, said they’ve been calling for such a committee for decades.

“This move demonstrates the government is listening,” said Fox. “I suspect, because of the impending election, their listening skills are potentially a little sharper than they normally are.”

Fox said the partnership came from “a place of long frustration” as provincial conservation officers kill more than 500 black bears every year on average, and the public is “no longer tolerating this kind of approach.”

“I think that the conservation officer service and the B.C. government are aware they need to change, and certainly the public has been asking for it,” said Fox.

Fox said there’s a lot of optimism about the new partnership, but, as with any government, there will likely be a lot of red tape to get through.

“I think speed is going to be important, whether or not the committee has the ability to make change and make change relatively quickly without having to study an issue to death, ” said Fox.

This report by The Canadian Press was first published Sept. 9, 2024.

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