The markings can fade – especially if it rains, depending on what the substance used is. Some minor marking may not be as a result of human intervention, but with the excessively marked hogs it seems the most likely explanation. Some people even admit that they paint hogs. But it seems too much of a coincidence that the excessive markings tend to appear on/after a Friday or Saturday night (plus Sunday nights on Bank holiday weekends). Also some of the marks reported are things like crosses and geometric designs which it also seems very unlikely that the hogs would manage to achieve by mistake.
Sometimes when the hogs have a scuffle they can, for instance, get some of the substance on their faces where they biff another hog which has some substance on him. The hogs can also get spots at a certain place on their sides if they have scratched there with ‘mucky paws’ – it is sometimes possible to see them scratching in the exact same area. Those sorts of markings tend to disappear quite quickly, especially if it rains and tend to appear on random nights. But also if a hog has ticks it can sometimes show up as (fairly small) spots below the spines on camera images.
I am wondering how it has ‘in some cases been proven not to be the case’ that ‘that people paint hogs’. But, I haven’t come across any information where it has been proven not to be the case that some people mark hogs.
Some rescues apparently mark hogs on release to make them easier to follow, but hopefully that would be with a discreet mark using water based paint – which should eventually fade.
Identifying hogs by their natural (facial and skirt) markings is the best way to observe hogs’ behaviour and is not as difficult as may first appear.
