Have you ever wondered how tigers are such good predators? Or why the bright orange of their fur isn’t an immediate warning sign to the creatures they prey on?
The answer is closer to home than we may realise. Tigers and many of the animals they hunt are colour blind. More specifically, these animals are dichromats.
Dichromats are animals with only two types of functioning cone cells, as opposed to humans, who are trichromats (with three). Red-green colour blindness in humans can result from altered cone photopigments, whereas in dichromats, one type of cone is not present at all, making animals like tigers effectively “orange-green” colour blind.
These cones are what help our brains interpret light. Most animals can see the entire visible light range of 380nm to 750nm (1). Light enters the eye and is detected by photoreceptors in the retina, which are a mixture of rods and cones. These cells send signals along the optic nerve to the visual cortex in the brain, where they are processed and interpreted. Different signals are directed to the brain depending on which photoreceptors detect the light, so having more or less specialised cones plays a big part in how we perceive the world (1).
Trichromats, like humans, can distinguish a broader range of colours than dichromats. Their three types of cones are most sensitive to short wavelengths (blue and violet light), medium wavelengths (green and yellow), and long wavelengths (orange and reds). Dichromats, however, group medium and long wavelengths together for interpretation by the brain, which contributes to their limited ability to distinguish between green, yellow and orange.
Most mammals have dichromatic vision and have not evolved beyond that, which may seem odd, as you’d think it would be a great adaptation for deer and wild boar (the most common prey of tigers) to be able to spot their predators amongst the greenery of their jungle habitat. However, their visual systems prioritise a different external factor: these animals are crepuscular. This means they are most active during twilight hours (just before sunrise and just after sunset). Their visual systems are adapted to seeing in dimly lit conditions, rather than distinguishing a wider range of colours. They can actually see up to 18 times better during these hours compared with typical human vision (2).
Humans have been primarily daytime creatures for the last 52 million years. Our trichromatic vision is helpful beyond this; we are able to use colour distinguishability to spot ripe fruit amongst greenery and interpret each other’s moods better (by noticing blushing and inferring emotion (3).
Many animals can see beyond even our capabilities, such as butterflies, which can have up to 15 types of photoreceptor classes (4). Four of these are believed to be involved in distinguishing between different colours, while the remaining types are used to detect other stimuli, such as fast-moving objects hidden amongst plants. The photoreceptors of butterflies enable them to see beyond the human-visible spectrum and into the ultraviolet range, revealing colours we could never imagine.
So, while we may have pondered why the deer and boar are unable to spot the stark contrast of a tiger in the jungle, we now know that colour, light and the way all animals interpret them are much more nuanced than we might think.
References
1. Cleveland Clinic. Shaping up what you see: understanding rod & cone photoreceptors. June 5, 2024. Accessed October 26, 2026. https://my.clevelandclinic.org/health/body/photoreceptors-rods-and-cones
2. Deer Association. 7 facts about deer vision hunters should see. October 26, 2022. Accessed October 26, 2026. https://deerassociation.com/facts-about-deer-vision/
3. Why is human color vision so odd? The Leakey Foundation. Accessed October 26, 2026. https://leakeyfoundation.org/why-is-human-color-vision-so-odd/
4. Arikawa K. The eyes and vision of butterflies. J Physiol. 2017;595(16):5457-5464. doi:10.1113/JP273917
Back to
Issue 11
