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Polar bears typically use sea ice to hunt, but a newly identified group has found another strategy.Credit: Patricia Hamilton/Getty
These polar bears survive without sea ice
An isolated population of polar bears has been discovered in southeast Greenland, which is free of sea ice for most of the year. Polar bears (Ursus maritimus) typically need sea ice to survive, so the discovery is raising hopes that some members of the species might survive the loss of ice caused by climate change. The group, consisting of 27 adult females, has adapted to hunting on the ice that has calved off glaciers — called glacial mélange.
Craft will ambush an as-yet-unknown comet
The European Space Agency (ESA) has approved a new mission, called Comet Interceptor, which will launch without any specific target in mind — instead lying in wait for a visitor from the outer Solar System, or even from another star. The goal is to find a pristine comet on a wide orbit taking hundreds of years, known as a long-period comet, that is entering the Solar System for the first time. It will be the first probe to be parked in space, ready to fly to a target at short notice.
A bug’s life, tracked in your tea
The DNA of more than 1,200 species of invertebrate, including spiders and insects, were found on shop-bought samples of tea and dried herbs. Sounds gross, but these were not bug remains — they were traces of environmental DNA (eDNA), which organisms shed into their surroundings as they walked across, chewed on or otherwise interacted with the leaves. The goal, say researchers, is to better understand how insect populations have changed. “When insect decline studies were first published, a lot of people complained [that] there is no real long-term data,” says ecological geneticist and co-author Henrick Krehenwinkel. He was inspired by the specimen bank at his university in Germany that has been collecting tree samples for 35 years. “And what I asked myself is, ‘Couldn’t you also monitor the DNA of the insects which have lived on this leaf?’”
The Scientist | 7 min read & Nature Research Highlight | 1 min read (Nature paywall)
Reference: Biology Letters paper
Features & opinion
‘Fusion seemed simple and thrilling when he explained it’
Eisuke Tada, the acting director-general of the ambitious ITER experimental fusion reactor project, recalls his predecessor Bernard Bigot, who died last month, aged 72. Bigot took on ITER in 2015 and is widely credited with bringing soaring budget and scheduling overruns to heel. Tada recalls Bigot’s quiet determination and warmth. “To his grandchildren, he explained his role at ITER as like that of a builder of a medieval cathedral who would not live to see the final masterpiece.”
Futures
An immortal grandmother and a customer service agent ponder the best way to spend a lifetime in ‘We regret to inform you that your choice of Deathday is no longer available’ — the latest short story for Nature’s Futures series.
Five best science books this week
Andrew Robinson’s pick of the top five science books to read this week includes how to solve the plastic problem, a highly illustrated history of life and a complex but readable study of ocean governance.
Podcast: How the Black Death got its start
The Black Death is estimated to have caused the deaths of up to 60% of the population of Europe. However, despite extensive research, the origin of this wave of disease has remained unclear. Now, by using a combination of techniques, a team has identified a potential starting point in modern day Kyrgyzstan.
Nature Podcast | 32 min listenSubscribe to the Nature Podcast on Apple Podcasts, Google Podcasts or Spotify.
