Lemurs’ neck bling tracks siestas, insomnia. Duke Research Blog, November 5, 2013. The fancy neck charm this lemur is wearing is no fashion accessory. Weighing in at just under an ounce, it’s a battery-powered data logger that measures light exposure and activity levels continuously over many days. Researchers outfitted twenty lemurs at the Duke Lemur Center with the special gadgets to study the animals’ daily ups and downs. The results could help researchers understand the sleep disturbances common among people with Alzheimer’s or other forms of dementia, and whether light therapy could help reset their internal clock for a more solid night’s sleep.