Chameleons' Eyes Are More Dependent Than Thought Before

Chameleons are famous for their unique visual system, where each eye can move separately, allowing them to scan their surroundings monocularly. However, this study by Ketter Katz et al. (2015) challenges the idea that their eye movements are truly independent, showing coordinated tracking behavior when confronted with two separate visual targets.

Key Findings

• When chameleons focused on a single moving target, both eyes remained fully independent, showing typical asynchronous movement.

• When presented with two simultaneous moving targets, their eyes continued to track independently at first but eventually coordinated, switching to a binocular fixated state once one target was prioritized.

• Smooth transitions between independent and coordinated eye movements suggest an underlying neural mechanism that governs visual integration when processing multiple stimuli.

Implications for Vision Science

This research reshapes the understanding of chameleon vision, indicating that their eye movements are flexible rather than strictly independent. It suggests their brain actively synchronises eye movement when needed, which could provide insights into visual processing in other vertebrates.

Ketter Katz, H., Lustig, A., Lev-Ari, T., Nov, Y., Rivlin, E., & Katzir, G. (2015). Eye movements in chameleons are not truly independent - evidence from simultaneous monocular tracking of two targets. Journal of Experimental Biology, 218(13), 2097–2105. https://doi.org/10.1242/jeb.113084