Hi Phileaus
What you are describing sounds like a well documented behaviour called self annointing. It’s isn’t completely clear why the hogs do it, but it’s thought that sometimes it’s in response to certain smells – which it sounds as if it was in the case you describe. The hogs get into those strange positions and spread frothy saliva over themselves. One study did suggest that more males self annointed than females – you mention that the hog was an aggressive one – which usually indicates that they’re males.
In the short term this could look like blobs or possibly even streaks, but if it was only saliva, would not last for any substantial amount of time as artificial marking of hogs by humans does. It’s possible that on occasion some other substance becomes mixed with the saliva. But it’s thought that not all hogs display this behaviour, so it would not account for the numbers of hedgehogs which are artificially marked, nor the patterns they are sometimes marked with, etc.
The most dominant hogs aren’t always the biggest ones, so it’s possible that it was more dominant than the larger one and sometimes they don’t always seem to have time to eat much before they tear off somewhere else!
You are, though, very lucky to have seen the self annointing behaviour – not everyone even ever sees it. It would be interesting to know if the same hedgehog continued with the behaviour on different days and whether it was triggered by the same place.
