Rod cells are specialized photoreceptor cells located in the retina of the eye. They are highly sensitive to light, allowing us to see in low-light conditions. Rod cells do not detect color; instead, they help us perceive shades of gray, making them essential for night vision. These cells contain a pigment called rhodopsin, which changes shape when exposed to light, triggering a signal to the brain. Rod cells are more numerous than cone cells, another type of photoreceptor responsible for color vision, and they play a crucial role in our ability to navigate in dim environments.