Well , over the years it has been variable, some years some adults dont go to sleep at all. At least those that we see on camera, who are well used to getting a regular source of food, and are probably fat [relatively] and in good condition. We have seen them running around in pretty cold conditons, seemingly quite happy.
However, those that are not on camera, and thus not being observed, and hence dont know about the abundant food source [ circular argument] are near to starvation at this time of the year, and hence their only strategy metabolically, is to go into dormancy [ and take the risk]. But as we dont see those we have not got a clue.
However, our hedgehog rescue centre does report that it is just not uncommon for some hogs never to go into dormancy regardless. But as you say, it is a matter of metabolic conditons. [Temperature, Fat, Nest Insulation, Food Type and Availability and Air Pressure/Temp* [ ie gut air pressure] as to whether they are conditioned to go into torpor or not.] All we can do is keep watching are reporting.
Neighbours are also watching out, so will report any further sightings
