Pigs can use their brainpower to avoid the fighting that usually occurs when they are mixed together on farms, according to Dr Mike Mendl from the University of Bristol speaking at the BA Festival of Science [11.30hrs 11 September 2002].
The researchers have found that when competing for a hidden snack, pigs don’t simply rely on muscle to get to the food first, but can use subtle behaviour to outwit their competitors. For instance, if they know where food is, they learn to approach it when other pigs are not looking. “This sort of behaviour suggests that pigs can compete with each other in quite complex and ‘cerebral’ ways,” says Dr Mendl, who has worked with Dr Suzanne Held from the University of Bristol and Professor Richard Byrne of the University of St Andrews. “We are now looking at whether they can size-up competitors and avoid physical confrontation. If given the opportunity, can a weaker, less aggressive pig tell that it will be defeated by a stronger animal and back down before a fight takes place? This ability is certainly seen in some wild animals, and minimises injury to both competitors.”
Pigs, like humans, differ greatly in temperament. Some are more aggressive, and quicker to fight, than others. Research at Bristol, together with studies by Dr Hans Erhard at the Scottish Agricultural College, suggests that when pigs of similar aggressiveness are mixed, more fights occur than when pigs of differing aggressiveness meet. This suggests that pigs can assess large differences in their fighting potential and use their brainpower to sort out their social status without resorting to fighting. Once this is done, pigs need to recognise and remember their group-mates to maintain the social order. How this is achieved is not clear, but research indicates that pigs can distinguish odours from different individuals.
Ultimately, this work may help farmers to minimise damaging fighting on pig farms by using individual recognition and assessment behaviour. It may also be possible to selectively breed pigs that are naturally less aggressive.
Biotechnology and Biological Sciences Research Council (BBSRC). September 2002.