Baby T. Rex were tiny but deadly

Hello Nature readers,
Today we hear that baby Tyrannosaurus were not to be messed with, discover the first genetic clues for borderline personality disorder and step closer to understanding the wasting and fatigue that often accompanies cancer.

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Do not try to pet that baby T. rex

“Tyrannosaurus were unsafe at any size,” says anatomist Eric Snively, a member of a team who analysed the teeth and foot bones of young dinosaurs to understand their behaviour soon after hatching. “Babies were quickly out of the nest and killing the heck out of things.” Tyrannosaurus rex fossils reveal that tiny hatchlings “were smashing into the bones of their food, just like giant adults”, says Snively.

Genetic clues to personality disorder origins

Researchers have identified 11 locations in the human genome, and nine functional genes in or near these areas, that seem to be linked to borderline personality disorder (BPD) — the first evidence of genetic risk factors associated with the condition. The findings come from the largest genome-wide association study of BPD so far, including data from more than 12,000 people with the condition. The study is “an extraordinary step up from where we’ve been previously, with virtually no research being conducted on the condition at scale,” says psychiatrist Andrew McIntosh.

Chinese AI model could rival US mainstays

Last week, Beijing-based Moonshot AI unveiled ‘Kimi K3’, a large language model that the company says can handle large swathes of text, and match or outperform US models on tasks such as coding. The open-weight model has generated a buzz among some researchers that use AI models, partly because it’s well-tuned for running AI agents, a capability that made its predecessor Kimi K2.5 so popular in China. But K3 might not be made widely available internationally, partly because of Chinese policies that could limit the use of its domestic AI models overseas.

A fresh look at cancer’s co-conspirator

An influx of studies is shedding new light on cachexia, a syndrome that causes muscle wasting and reduced appetite and affects up to 80% of people with cancer. The research has repositioned the condition as a whole-body syndrome of metabolism gone haywire, with psychological symptoms as well as physical, and has unearthed clues as to how the brain orchestrates it. And a handful of companies, including pharma giant Pfizer, are testing medicines for cachexia, raising hope that a treatment might be on the horizon.

How to manage the risk of deep-water gas

Until world economies make the essential transition to low-carbon forms of energy, natural gas will be crucial, argues Yuxin Zhao, who is a scientist affiliated with one of China’s state petroleum companies. He explores how the gas resources that lie beneath fragile, remote deep-sea ecosystems can be best exploited. “The answer is balance — for which access is a privilege earned with proof of responsibility,” he writes, pointing to China’s ocean-governance approach as an example of how to “turn ecological restrictions into requirements for development”.

Teens’ bad decisions are not all irrational

Blaming teenagers’ undeveloped brains when they don’t choose the ‘sensible’ path — by retaliating against an insult in a school corridor, for example — does them a disservice, argues evolutionary criminologist Evelyn Svingen. “Teenagers do weigh up what they are doing. The costs that weigh most heavily on them are social, and adults consistently underestimate how heavy they are,” she writes. “The teenager who hits back in the corridor is running on an ancient programme.” She offers advice on how schools and parents can “create an environment where the rewarding thing to do and the sensible thing to do point in the same direction”.