Human vision relies on cells in the retina that are known as rods and cones. Cones help us to see color, but only when there is enough light. Rods take over in low-light conditions, but we see only black-and-white images. Frogs and toads, however, have two types of sensitivities in their rods, allowing them to see colors even in the dark. In a series of experiments in 2017, researchers put frogs in completely dark environments and found that they were able to discern colors and find the exit -- much like the conditions they frequently face in real life.
Never in the dark:
- “It’s amazing that these animals can actually see color in extreme darkness, down to the absolute threshold of the visual system,’ said professor Almut Kelber. “These results were unexpected.”
- In other experiments, researchers studied how frogs and toads use their color vision when searching for a mate or hunting for food. Turns out that color means little in the hunt for a significant other.
- Frogs are nocturnal, and their night vision benefits from a layer of tissue in their eyes called the tapetum lucidum. Animals with this tissue (such as cats) appear to have “eyeshine” in photos.