Just to clarify the Hog I saw flattening itself was seen at night, not during the day and was a regular that I observed daily right up until hibernation. She only ‘splatted’ on really muggy evenings and she was eating and drinking as normal. I have a friend who is a vet and she told me it could be a cooling down mechanism. I do worry about any behaviour out of the norm so it is helpful to have a vet on hand to ask about these things! She often treats wild hogs and has a list of local carers on hand for advice.
It is fascinating to see all this behaviour. I wonder why hedgehogs are not more widely studied to help solve these mysteries!