Why are some animals unable to see colors?

Hummingbirds see colors that we can't even imagine

Over three seasons in the field, the scientists carried out a total of 19 experiments from 2016 to 2018 and counted around 6,000 hummingbird visits to their feeding grounds. By tracking which donor the birds went to, the researchers were able to show that broad-tailed hummingbirds consistently chose the feeding site with the fresh water - regardless of whether it was a non-spectral or spectral hue.

“Even if the colors looked the same to us - for example, if the birds had to choose between a feeding place in UV green and one in normal green - they could see the difference,” says Stoddard.

"It was an amazingly bold experimental approach," wrote evolutionary biologist Karen Carleton of the University of Maryland at College Park via email. The study shows that "through the eyes of a hummingbird, the world could look very different from what we see".

Amazingly colorful world

Color perception helps animals choose their food and partners, as well as avoiding predators. For example, bees can see an ultraviolet pattern in yellow flowers that directs them to the nectar like a target. If we look at the same flower, we only see one yellow flower.

To find out why hummingbirds see such a variety of colors, Stoddard and colleagues analyzed existing data on the colors of various plumage and plants. They discovered that hummingbirds are able to see 30 percent of birds' plumage and 35 percent of plant colors in non-spectral hues that "humans cannot even imagine," says Stoddard. This ability is likely to aid the tiny birds in tracking down a wide variety of plants and their nectar.

Video: Untamed with Filipe Deandrade: Hummingbird