Artificial lighting from sources as common as streetlights may disrupt the circadian rhythms and immune systems of mammals, and even raise the risk of death, a new study by Tel Aviv University suggests. Hagar Vardi-Naim, a doctoral student in life sciences, examined the effects of artificial lighting on the immune systems of two related species of small rodent — the golden spiny mouse and the common spiny mouse. Both live in the Israeli desert and share the same geographical habitat. But while the golden spiny mouse is active during the day, the common spiny mouse operates at night. The animals were transported from the Judean Desert to outdoor enclosures at Tel Aviv University’s Zoological Research Garden, where some were exposed to artificial light at night. “Large parts of every mammal’s body, including our own, are regulated by an internal biological clock,” Vardi-Naim explained.…