A novel system for bi-ocular eye-tracking in vertebrates with laterally placed eyes

1. Animals use vision to gather information about their environment and then use that information to make behavioural decisions that affect fitness. They will often move their heads or eyes to inspect areas of interest with their centres of acute vision, such as foveae, to gather high resolution information about potential mates, predation risks, or other aspects of the environment. Few studies to date have been able to accurately determine where laterally eyed animals direct their visual attention and how they use their eyes to gather information. 2. We present a non-invasive eye-tracking system that can simultaneously track the gaze of two eyes. This is particularly useful for studying animals with laterally placed eyes (most vertebrates) where the two eyes are viewing different images. This system can also accommodate comparative studies using animals of varying size, including small animals that are not frequently used in eye-tracking studies due to constraints of existing eye-track...