March 2026: Wine's new study: Artificial nighttime light disrupts immune systems and double mortality in mammals

A new study, published in Environmental Pollution, led by Prof. Yariv Wine, Edmond J. Safra affiliate, Hagar Vardi-Naim, a PhD student in his lab, and, Prof. Noga Kronfeld-Schor, TAU Rector (Life Sciences), reveals that artificial light at night may harm the immune system and increase the risk of death in mammals.

The team studied two species of desert rodents, the golden spiny mouse (active during the day) and the common spiny mouse (active at night). Unlike many studies that rely on laboratory animals kept in highly controlled environments, this research used animals living under near-natural outdoor conditions. This approach allowed the researchers to better capture how biological systems function in the "real world", where animals are exposed to natural environmental fluctuations.

The animals were kept in outdoor enclosures that closely mimicked their natural habitat. Some were exposed to low levels of artificial light at night, similar to street lighting, while others experienced only natural light from the sun, moon, and stars.

The researchers found that even this mild nighttime light disrupted the animals' internal biological clock, which normally controls daily patterns in the immune system. Under natural conditions, immune activity follows a clear rhythm across the day. However, exposure to artificial light eliminated these patterns, meaning that the immune system lost its sense of timing.

This disruption had real consequences. Animals exposed to artificial light showed a much higher mortality risk, more than twice that of the control group. Although the exact cause of death was not determined, the findings suggest that disturbing the body’s natural rhythms may weaken its ability to cope with stress, infection, or other challenges.

The study suggests that nighttime light pollution is not just an environmental or aesthetic issue, but rather that it can directly affect biological systems that are essential for health. It also underscores the importance of studying animals in ecologically realistic settings, facilitating the discovery of effects that may be missed in traditional laboratory studies. Notably, since many animals, including humans, rely on similar internal clocks, these findings may have broader implications for ecosystems and public health.

The study was featured in the Israeli newspaper Haaretz.