Daily briefing: The mystery of the ‘little red dots’

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Edible battery can power devices in the body

A battery made with a substance similar to edible rice paper can power ingestible medical devices, and breaks down into materials that can be absorbed by the body after use. The tiny power source uses electrodes made of magnesium and molybdenum trioxide — two micronutrients that the body needs in small amounts — and a biodegradable ionic liquid as an electrolyte. The battery has so far been tested in pigs, with the hope that it could one day be used to provide electricity for ingestible personalized devices in people.

Nature | 5 min read

Reference: Nature Chemical Engineering paper

Epigenetic editing could treat hep B

A treatment that adds chemical tags to the genome of the hepatitis B virus (HBV) can shut down the virus’s gene activity and prevent it from producing viral particles. The therapy, which achieved promising results in experiments on human liver cells and in mice, could be used to treat chronic hepatitis B, a lingering liver infection that affects more than 250 million people worldwide. A clinical trial to test the treatment in people is already under way, with the first participant receiving an intravenous infusion in January this year.

Nature | 5 min read

Reference: Nature Biomedical Engineering paper

Dolphin eats fish vomit after fast chase

Researchers have recorded a rare instance of a food-stealing behaviour called kleptoparasitism in a common bottlenose dolphin (Tursiops truncatus). The team filmed the dolphin, known as Bubbles, repeatedly chasing individual bigeye trevally fish (Caranx sexfasciatus) until they threw up — and then eating the vomit. Bubbles might have originally intended to eat the fish, but decided that the vomit was an easier meal, says marine ecologist and study co-author Asia Armstrong. Or, it might have wanted the sick all along, since trevally are large and would be tough for a dolphin to chew.

Science | 4 min read

Reference: Ecology and Evolution paper

Image of the week

New Zealand’s Bird of the Year is the karure, or black robin (Petroica traversi), and you can see why: this little creature is small, dark and handsome. This tenacious species has bounced back from just five birds in 1980 — only one of which was a fertile female — to 350 adults living on two islands free of invasive pests. Hats off to Old Blue, mother of her kind. (CNN | 5 min read) (Dave Boyle)

Features & opinion

We must prepare for super El Niño

“A serious El Niño caught the world off guard in 1982, when reliable early-warning systems barely existed,” writes climate scientist Zeke Hausfather, who maintains a real-time dashboard that includes data about the weather event. “In 2026, there is no such excuse.” Governments have only a few weeks to act to prepare, for example, for drought in southern Africa. Priorities include distributing drought-tolerant and early-maturing crop varieties in high-risk areas and expanding programmes that provide support when harvests fail.

Nature | 7 min read

Sugar-rationed babies saw host of benefits

A study of people who lived their early life during post-war sugar rationing in the United Kingdom found that they had lower risks of all-cause dementia, Alzheimer’s disease, depression and anxiety than people born after rationing ended. A separate study found they were much less likely to develop certain cancers later in life. Even in adulthood, low-sugar babies continued to consume less sugar and had healthier diets overall. “This suggests that the level of sweetness people are exposed to very early in life may shape their taste preferences for a long time,” says economist Weilong Zhang, who co-authored the latter study.

People | 4 min read & The Conversation | 6 min read

Reference: npj Aging paper & PNAS paper

Little red whats?

Little red dots (LRDs) sound innocuous, but they present one of the most exciting mysteries in cosmology. Many have been observed, thanks to the unprecedented window into the distant Universe that has been opened by the James Webb Space Telescope. But what are these enigmatic objects from the dawn of time? An initial consensus has coalesced around them involving black holes of some kind — perhaps primitive versions of the active galactic nuclei we see in the more recent Universe. But other, more exotic, theories have also emerged.

Nature Astronomy editorial | 6 min read or read the whole LRD collection

Today I’m impressed by Incendiamoeba cascadensis — the fire amoeba — which thrives in a 63 ℃ hot spring in California. It’s broken the heat tolerance record for complex life, recovering from a bout of 70 ℃ in the lab.

While I ponder a trip to the sauna, why not send me your feedback on this newsletter? Your e-mails are always welcome at briefing@nature.com.

Thanks for reading,

Flora Graham, chief editor, Nature Briefing

With contributions by Jacob Smith

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