The chameleon of colour vision
Pacific pink salmon can change their colour vision so they are sensitive to different colours at different stages of their lives. Opsins, the visual pigment proteins that respond to specific colours, were assumed to remain constant throughout an animal’s life. In humans, for example, the combination of red, green, and blue-sensitive pigments combine to produce the colourful spectrum we observe. However, Canadian scientists report that different pigments are produced by the salmon to adapt to its changing lifestyle, as it migrates from shallow rivers to deeper waters during its aging process. Some colours of light, such as blue, can travel further through water than other colours. The type of light that you can see varies with the depth of water. The salmon switches its visual sensitivity from ultraviolet to blue as it moves into deeper water by producing opsins with different colour sensitivities. This discovery represents a new mechanism in the regulation of colour vision in animals.
Haowei Sun
Source: Nature
