Pig tails

Curly tails occur in domesticated pigs, while wild boars have them straigh. Swine use tails express a range of emotions from excitement, fear, anger, to hapinnes. Like dogs, pigs can wag their tails! During the domestistication process swine tails started to curl, but scientists still are not sure why this happens. One hypothesis is that it is an adaptation to avoid tail biting in overcrowded captive environments. A recent study of pig behavior and neuro-cognition shows that for most pigs the tails curl to the right-side direction. This helps to better understand the social function of this organ and how it is connected to hemispheric dominance in mammals, or the tendency for some cognitive processes to be specialized to one side of the brain or the other.

You can read this paper here: Behavioural lateralization in domestic pigs (Sus scrofa)—variations between motor functions and individuals

Abstract: Motor lateralization is hypothesized to depend on the complexity of the motor function, but it might at the same time reflect hemispheric dominance within an individual across motor functions. We investigated possible motor lateralization patterns in four motor functions of different complexity (snout use in a manipulative task, foot use in two-stepping tasks and tail curling) in the domestic pig, a tetrapod species relevant as farm animal but also as a model in human neuroscience. A significant majority of our sample showed individual biases for manipulation with their snout and for curling their tail. Interestingly, the tail curling was lateralized towards the right at the population level and showed stronger lateralization patterns than the snout. Using a cluster analysis with combined tail and snout laterality, we identified groups of individuals with different lateralization patterns across motor functions that potentially reflect the individuals’ hemispheric dominance. To conclude, our results suggest that pigs show lateralization patterns that depend on the motor function and on the individual. Such individual lateralization patterns might have broader implications for animal personality and welfare. Our study lays the methodological groundwork for future research on laterality in pigs.