Cows see danger better on the left

By Marina Kamenev 23 November 2010
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Like humans, cows use the each side of their brains for different functions, such as perceiving possible threats.

IN HUMANS THE left and right side of our brains have different functions, and it now turns out the same is true of cows, which use one side to detect possible dangers.
Research from Professor Clive Phillips and Dr Andrew Robins at the University of Queensland has revealed that cows are better able to perceive danger if they’re approached on their left side. “When they see an unfamiliar person they will rearrange themselves until they are looking at the person with their left eye,” says Clive.

This curious behaviour is the result of something called lateralisation the concept that the two hemispheres of the brain are responsible for different processes, emotions and responses.

Crossed wiring

In vertebrates, including humans, the right hemisphere is known for detecting and responding to predators, while the left reacts to prey or food. Because the right side of the brain controls the left side of the body and vice versa, the left eye may be better adapted to processing dangers.

In humans, the right side of the brain is responsible for visualisation (such as facial recognition) and processes information in a more feelings- or emotion-led, holistic way; whereas the left side deals with language, maths and logical processing. One theory about why the left side is considered to have an advantage, Clive says, is that the wiring between the left side of the body and the right hemisphere has a faster connection than the reverse, allowing the body to react  in a flight or fight, intuitive way to rapidly approaching predators.

Andrew and Clive’s study followed on from Russian research showing that cows fed from a tractor moving past on the left produced 10 per cent less milk than cows which were fed from the right.

Overwhelming results

Andrew tested the theory that cows would be similarly affected by a perceived threat, by walking through a herd and recording the cows’ response. He then followed up by walking through the herd with a range of objects the animals would find mildly stressful such as a brightly coloured umbrella that he opened and closed rapidly, a wide-forked apparatus, and an idle whipper-snipper engine.

The results were overwhelming, the scientists found. “We never expected that magnitude of response,” Clive says. “The majority of the cattle would cross over so that Andrew was on their left and more specifically so that he was visible from their left eye.”

While this is the first time the lateralisation effect has been confirmed in cows, it has been found in other animals. Lesley Rogers, an Emeritus Professor at the University of New England, in Armidale, New South Wales, discovered lateralisation in chicks in the 1970s. Lesley has since seen evidence of lateralisation in a range of species including fish, toads, horses, and dunnarts. The idea that horses are more sensitive to objects that appear on their left, may be of importance, as that is the side on which humans typically mount them. Cattle are also usually handled on their left-hand side.

The scientists will expand on their work to figure out how farmers may be able to apply the research. While the results suggest it’s better to walk towards cows on their right so you aren’t perceived as a predator, Andrew suggests the convention of walking on an animal’s left is correct.

“If cows perceive you as the main threat than they are more focused. They are less concerned with other things that might scare them,” said Andrew. “It might just be a case of better the devil you know, than the devil you don’t know.”

VIDEO: Researcher Dr Andrew Robins walks through a herd of cows to see which way they might turn.