Yellow rat snake head shaking for no reason

[Sean32917]

Hi all

First time post as I'm worried about my yellow rat snake and Google isn't producing any answers for me.

He's a wild caught snake I caught in the wife's hanging plant while he was hunting a lizard about five years ago - he was maybe 2.5 feet in length then but is 4+ now.

Extremely friendly, social and alert once he got used to me, always rearing up to look at me when I come to his tank and slithering over to sniff my hand - I swear he's more dog than snake with how he acts.

He finished a clean shed last weekend in March and took a small rat without issue middle of last week.

For the last few days he's been very lethargic and keeping to his hide then today when I saw him out and about I opened his tank to pet him and say hi and he barely reacted to me.

More distressing though is that I noticed that his head was trembling, kind of shaking back and forth, left to right somewhat quickly and what appeared to be in an involuntary manner.

He's never done this before and did not demonstrate his normal alertness either, not raising himself up to sniff me nor to crawl onto my arm as he's want to do.

Google says they live 10-15 years in the wild and up to 20 in captivity so I'm thinking this is sickness of some sort rather than old age?

He's a good eater, taking a small rat and occasionally a bonus rat pup if the orange corn snake doesn't eat his dinner with his food being store bought white rats from a local place that specializes in snakes and exotic reptiles.

Any help would be appreciated as Old Yeller is a loved member of our family - even my mom, who's afraid of snakes, will walk over to his tank and say hi to him when she visits thanks to how friendly and personable he is.

Thank you.