How Underground Living Changes the Eyes of Mandarin Voles

A Unique Adaptation to Darkness

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.

Key Findings

• Blurry Vision and Poor Distance Judgment: Mandarin voles don't see very well. Their vision is blurry, and they can't judge distances well.
• Structural Changes in the Eye and Brain:
• Retinas: Have fewer rods (which help see in the dark) and more cones (which help see colors).
• dLGN (Dorsal Lateral Geniculate Nucleus): Smaller but with more connected neurons.
• Primary Visual Cortex: Looks similar to that of other mammals.

Genetic Insights

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.
• Genes for proteins that help the eye work properly.

Implications for Adaptation

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.