Evolution of human colour vision similar. Tritanopes are missing the short wavelength sensitive opsins and see short wavelength colours in a green hue and dim compared to other colours. They may also see some short wavelength colours as black. Other perception problems include distinguishing yellow from pink or purple colours being perceived as shades of red. Researchers have found that trichromacy has advantages over dichromacy or anomalous trichromacy at further distances. This is believed to occur because visual cues such as shape decrease for colour vision as distance increases for targets of a smaller size. Using tests for spotting fruit pieces in bushes at distances
Evolution of human colour vision with limited colour vision. This is believed to have also been influenced by life styles, including being predominantly nocturnal. There is little data indicating the advantages of UV vision in early human ancestors. Early human ultraviolet vision, or ultraviolet sensitivity, included sensitivity in the wavelength ranges between 400 and 10. These wavelengths are shorter than visible light but longer than X-rays. In some rare cases, some modern day humans can see within the UV spectrum at wavelengths close to 310. In other animals that possess UV vision such as birds, ultraviolet sensitivity can be advantageous for courtship and reproductive success.