How Underground Living Changes the Eyes of Mandarin Voles

Mandarin voles, small mammals that live mostly underground, have eyes that are different from their relatives that live above ground. Scientists wanted to see how living in the dark changes their vision. They compared Mandarin voles to Brandt's voles, which live above ground, and regular lab mice. The study found that Mandarin voles don't see very well. Their vision is blurry, and they can't judge distances well. This is because their eyes and brain parts related to vision have changed over time. For example, their retinas have fewer rods, which help see in the dark, and more cones, which help see colors. The part of their brain that processes vision, called the dLGN, is smaller but has more connected neurons. Interestingly, the primary visual cortex, where vision is interpreted, looks similar to that of other mammals. Scientists also looked at the genes related to vision in Mandarin voles. They found that some of these genes have become non-functional, or pseudogenized, over time. This includes genes for processing vitamin A, which is important for vision, and genes for proteins that help the eye work properly. These changes suggest that living underground has led to a decline in vision and changes in the structure of the visual system in Mandarin voles. This research gives new insights into how animals adapt to their environments. It shows that living in the dark can lead to significant changes in vision, both in structure and function. Understanding these changes can help us learn more about how mammals adapt to different habitats.