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Footprints at the excavation site.

Ancient footprints found at the New Mexico site. The tracks were dated to between 21,000 and 23,000 years old, and probably belonged to children and teenagers.Credit: National Park Service, USGS and Bournemouth University

Human footprints are oldest in the Americas

Human footprints from an ancient lakeshore in what is now New Mexico seem to be between 21,000 and 23,000 years old. If the dating is accurate, the prints represent the earliest unequivocal evidence of human occupation anywhere in the Americas. The footprints contribute to ongoing debate about whether human settlers from Siberia skirted down the Pacific coast of the Americas or waited until ice-age glaciers retreated from inland routes.

Nature | 6 min read

Reference: Science paper

Drug-resistant malaria has arrived in Africa

A long-feared milestone has arrived: malaria parasites in Africa have developed resistance to a key family of drugs used to protect against them. The first signs of resistance to the ‘gold standard’ treatments for malaria — the drug family including artemisinin and its derivatives — appeared in Cambodia in the early 2000s. For resistance to now hit Africa is particularly dire because more than 90% of malaria cases and deaths worldwide occur on the continent.

Nature | 6 min read

Reference: New England Journal of Medicine paper

SARS-CoV-2 doppelgangers found in bats

Scientists have found three viruses in bats in Laos that are more similar to the virus that causes COVID-19 than any known viruses. Their discovery underlines that there are numerous coronaviruses with the potential to infect people. Samples taken from horseshoe (Rhinolophus) bats in caves in northern Laos contained viruses — named BANAL-52, BANAL-103 and BANAL-236 — that are each more than 95% identical to SARS-CoV-2. “When SARS-CoV-2 was first sequenced, the receptor binding domain didn’t really look like anything we’d seen before,” says virologist Edward Holmes. The Laos coronaviruses confirm these parts of SARS-CoV-2 exist in nature, he says.

Nature | 5 min read

Reference: Research Square preprint (not peer reviewed)

Features & opinion

Horseshoe Crab in Mangroves, Limulus polyphemus, Cancun, Yucatan, Mexico.

Horseshoe crabs’ blood is blue: their oxygen-transport protein is copper-based.Credit: Getty

At the heart of life

A new book by zoologist Bill Schutt aims for the heart. Pump explores how multicellular organisms have found various ways to solve the same fundamental challenge: satisfying the metabolic needs of cells that are beyond the reach of simple diffusion. Rather than seeing humans as the highest peak on the evolutionary landscape, he celebrates everything from the Horseshoe crab’s copper-based blue blood to the hummingbird’s astonishing 1,260-beats-per-minute heartbeat.

Nature | 5 min read

Meta-analyses lessons from ivermectin

Data from individual participants in clinical trials are essential for understanding potential therapeutics for COVID-19, argue physician-scientist Kyle Sheldrick and colleagues. They point to some research into the use of ivermectin against COVID-19 that did not stand up to scrutiny. “Relying on low-quality or questionable studies in the current global climate presents severe and immediate harms,” argue the authors. They call for an urgent shift so that clinical research is seen as “a contribution of data toward a larger omnibus question rather than an assemblage of summary statistics”.

Nature Medicine | 5 min read

Futures: science fiction from Nature

In this week’s helping of short stories for Nature’s Futures series:

• A mysterious traveller, alone on the shifting surface of a tiny world, braces herself in ‘On the ice of Nix’.

• A few precious hours of digital-life-after-death allow for a final, delightful disobedience in ‘Last words and little rebellions’.

Five best science books this week

Andrew Robinson’s pick of the top five science books to read this week includes ocean politics, DNA history and a history of the climate experiment.

Nature | 3 min read

Podcast: seed-inspired floating sensors

In this week’s Nature Podcast, learn about tiny electronic devices that float through the air, which could offer a new way to monitor the environment. Plus, humans can adjust to an energy-efficient walking pace almost without thinking, and the viral shell that excels at delivering genome-editing tools.

Nature Podcast | 19 min listen

Subscribe to the Nature Podcast on Apple Podcasts, Google Podcasts or Spotify.

Quote of the day

“Among the unvaccinated, the virus travels unhindered on a highway with multiple off-ramps and refueling stations. In the vaccinated, it gets lost in a maze of dead-end streets and cul-de-sacs.”

No, vaccinated people are not ‘just as likely’ to spread the coronavirus as unvaccinated people, writes emergency-medicine physician and global-health specialist Craig Spencer. (The Atlantic | 5 min read)