Ann Arbor Times

A recent study from the University of Michigan has unveiled intriguing insights into the ultraviolet (UV) color patterns in snakes, a feature often overlooked due to human limitations in perceiving UV light. The research, published in Nature Communications, investigated how snakes utilize UV coloration and what ecological factors drive its evolution.

The study, led by Hayley Crowell, a doctoral student at U-M's Department of Ecology and Evolutionary Biology, discovered that UV color is prevalent across various snake species and is primarily used for predator avoidance. "A lot of UV color work is done in systems that we consider traditionally bright and colorful," said Crowell. "However, there are a lot of groups, like snakes, that aren’t necessarily on people’s radar as a broadly colorful study system."

Researchers examined 110 snake species from different regions such as Colorado and Peru using specialized cameras to capture their UV reflections. The analysis focused on variables like age, sex, habitat type, evolutionary history, and predator visibility. It was found that arboreal snakes exhibited significant UV coloration likely due to camouflage needs against predators like birds.

An unexpected finding was the lack of sexual dimorphism concerning UV coloration in snakes. Alison Davis Rabosky noted this was surprising given the role reproduction plays in driving UV color evolution in other species. "I don’t think snakes are actually some kind of outlier doing color ‘differently’ than other animals," she said.

John David Curlis commented on the absence of sexual differences: "The fact that snake colors did not differ between the sexes may suggest that sexual selection may play less of a role."

Despite closely related species sometimes showing stark differences in UV reflection levels, researchers identified juvenile snakes often displayed more vibrant UV colors than adults.

Hannah Weller expressed excitement over the dataset's ability to highlight variability within snake species: "This amazing dataset really helped us start to understand just how variable a trait like this is."

The study aims to encourage further exploration into how organisms use color beyond human-visible spectrums.