It has been long established that environmental factors affect how animals’ colour develops. However, it remains unclear what drives and regulates the global patterns of colour variation over a long time scale.
A research team studied 10,638 images of 1,249 species of scaled reptiles to get closer to solving the mystery. By examining body mass, distribution by latitude and altitude, visibility, habitat type and activity time, the researchers were able to gain an insight into the intricate interplay between the variables that have shaped colour evolution.
“Colour evolves under the influence of several competing selection forces from different ecological and environmental factors. By identifying the driving forces behind global patterns of colour variation, we can gain a deeper understanding of how species can adapt to changing environmental conditions,” says biology researcher Jonathan Goldenberg who led the study at Lund University, and now works at the University of Oslo.
In the study, the researchers quantified the colour brightness of reptiles through image analysis. This was followed by an evaluation of how the six studied variables, and their underlying selection forces, affected colour development over the past 200 million years of reptile history. The results showed that light colours are consistently connected with open habitat over a long period.
“We also discovered that the rate of colour brightness evolution probably follows major changes towards a colder and drier climate. This suggests that reptiles have probably adapted their coloration to new habitats in response to changes in the landscape,” says Jonathan Goldenberg.
Thanks to the new results and the database of images that has been created, future research could gain deeper insights into how species might react to changing environmental conditions. This could guide preservation efforts and improve our knowledge of biodiversity and its dynamics.
“Scaled reptiles are the largest extant order of four-limbed animals. The study helps us to understand how climate change and habitat shifts may affect animals’ survival and adaptation in relation to colour. This is crucial for predicting the consequences of future climate change,” concludes Jonathan Goldenberg.
