Hello Nature readers,
Today we boggle at the best science images of the month, hear that industrialization might cause ‘inflammaging’ and engage with an effort to quantify the number of lives lost in Gaza.

The month’s best science images

This leaf scorpionfish (Taenianotus triacanthus) is one of many fish species to show biofluorescence: they absorb and re-emit light as brilliant glowing colours. A pair of papers out this month has offered fresh insights into the evolution of biofluorescence in fish, suggesting that it has evolved independently more than 100 times over the past 112 million years, and involves a greater variety of colours than was previously thought.

See more of the month’s sharpest science shots, selected by Nature’s photo team.

War has killed more than 84,000 in Gaza

Around 84,000 people died in Gaza between October 2023 and early January 2025 as a result of the Hamas–Israel war, estimates the first independent survey of deaths. More than half of the people killed were women aged 18–64, children or people over 65, reports the preprint study. The figure is independent from, and larger than, the count of 56,200 most recently reported by the Palestinian Ministry of Health.

Modern life might cause ‘inflammaging’

Chronic inflammation — which has long been considered a hallmark of ageing — could be a feature of living in an industrialized society. In a study of nearly 3,000 adults, researchers found that, in people living in Italy and Singapore, inflammation levels increased with age and were associated with illnesses such as chronic kidney disease. In people living in Indigenous communities in Bolivia and Malaysia, neither of those things were true. The results suggest that “our assumption that inflammation is an inexorable, inevitable part of ageing is not true”, says biological anthropologist Thomas McDade.

The road map to 28-day embryo research

Extending the length of time for which human embryos can be grown in culture from 14 to 28 days would offer the promise of unique scientific and clinical insights, but requires careful ethical oversight, argues a group of human-embryo researchers. To facilitate this transition responsibly, they recommend that policymakers and research institutions:

• Run pilot projects in a few accredited centres to assess the value add of the data gathered in the additional days.
• Ensure that anomalies trigger ethical ‘pause points’ at which ethics regulators step in to assess the next steps of a project.
• Make collected data and regulatory protocols transparent and accessible to the public and research communities.

Chatbots need emotional boundaries

“We’ve built machines that sound like they care. Now, we must ensure that they don’t hurt the very people who turn to them for support,” writes clinical neuroscientist Ziv Ben-Zion. He recommends mandatory safeguards for artificial-intelligence (AI) chatbots such as ChatGPT — including a ban on simulating romantic intimacy or engaging in conversations about suicide, death or metaphysics.