How cold is getting in the tank overnight ?
How long are the lights on each day ?
It's autumn where you live and he may be signally he's ready to go down (brumate) if your daytime and nighttime temperatures are too cold and the day cycle is too short.
Keep in mind that a lizard's metabolism is not like that of a mammal, when they are cold their metabolic rate and activity level reduces (they become lethargic and very sleepy and inactive).
You need
a basking spot at about 40oCelsius
and overnight temperatures kept above 21oCelsius (in my case about 22 - 24oCelsius year round c/- my reverse cycle split aircon system)
and a day cycle (basking and UV lights on) longer than 12 hours (I'd recommend 14 -16 hours , I run a permanent 15hr day cycle for my lot)
.... to keep your beardie more active.
I have a friend who breeds rankins and here is an extract from an email he just sent me - I asked him as I was unsure of proper conditions for a Rankins (I've not kept them)
The temperatures you will want to achieve are 40-43c in the hotspot with a cool spot of approximately 25-30c this may need to be achieved by using exhaust fans depending on how large your enclosure is and what heating methods are used. Night time heating isn’t really needed unless you live in very cold areas during winter in which 20-25c overnight should be enough to keep your little friends happy.
None of my pet lizards (beardies, bluetongues and water skinks) have ever brumated because I fool them into thinking it's always summer as above.
My lot don't stay up all day either, they bask for a while , and then nap here and there during the day between basking and thermoregulating periods.
If he's over 12 months old, in good health and got plenty of fat reserves, and he's emptied his bowls , it's OK to let him brumate if he really wants too.
Others can advise how to manage him while he's in brumation and how to adjust his tank temperatures and lighting schedule while he's in brumation, I've never had that problem so other than turning down the lighting schedule a bit and the temperatures and providing water when he comes out (as they can do for short stints to bask) to give him a drink I'm not sure what else needs to be done husbandry wise while a beardie is in brumation.
I think it's not a good idea to allow a beardie brumate in it's first winter .
BUT === If I remember correct he's a juvenile (9 month old) rankins.
So I'd definitely try to keep him active and feeding and basking and growing this winter as he's too young to brumate, so you need to provide overnight tank heating to keep him warm .
Best options are
a ceramic heat emitter controlled by a digital thermostat who's probe is near (inside maybe) his hide
or a heatpad (also controlled by a digital thermostat) placed under the tank
or sandwiched between two layers of tiles and placed under the hide - this is how I provide extra nighttime warmth =
viewtopic.php?f=75&t=224976 ) for when it gets chilly .
And you need to bump up his daytime zone temperatures and basking temperature (higher wattage basking globe) , maybe bump up his lighting schedule (hrs ON) and I suggest he should be still getting two live insect meals per day too.
I believe in really cold climates (like Canada and the really cold USA states) people run ceramic heat emitters in their tanks 24/7 to give both a daytime boost in temperature (as well as running larger wattage MVBs or basking spot globes over winter), and to keep the overnight temperatures above 21oCelsius.
The climatic conditions in the natural range (black soils region of Queensland) of rankins dragons are coolest days in winter is 24oCelsius and coolest overnight temperature in mid winter is 12oCelsius - the ground a few inches under stays about 21oCelsius even on the coldest night in winter and rankins will take refuge to avoid exposure to the colder overnight extremes).
