Most of us have preferences such as left- or right-handedness, and tend to favour one eye over another to look down a telescope. These biases are the result of brain lateralisation, with a dominant left side of the brain leading to right handedness, and vice versa. Many animals show comparable biases. Lesley Rogers believes a better understanding of these biases could be used to improve animal welfare. Rogers, of the University of New England, Australia explains her ideas in an article in CAB Reviews.
Horses, like many animals, show side bias (Fir0002/Flagstaffotos, see License).
The left hemisphere of the brain deals with repeated stimuli, paying attention and learning rules, whilst the right is more concerned with emergency responses to threats. Given the switch over between brain side and the part of the body that it relates to, this means that domestic chickens prefer to look at potential predators with their left eyes (associated with the right hemisphere), but to use their right eyes (and left hemisphere) to search for food, having learned rules for what is and isn’t food. Many animals respond more strongly to predators that approach them from the left.