Sick guinea pig

Question
I'm not sure how old my guinea pig is, I adopted him from someone else. I'm thinking he's around 3-4. He has suddenly become lethargic. He just sits in his cage, he doesn't run or jump around and he's not purring or chirping anymore. Any ideas?

Answer
Sadly these little guys don't show us their symptoms until it's almost always too late. Cavies do not have a long lifespan.  The average life of a guinea pig is only 4-5 years, but just as with humans they all age differently.

My oldest pig lived to be seven. That was a documented age, as she'd been born in my caviary and I had her pedigree. However, that's not the norm. I've had pigs pass at less than 4.

If he's already at the lethargic stage he is most likely going to pass in the next few days.
Once they stop eating and drinking they often put their head in the corner and wait for the end. That's always been a 'red flag' warning to any breeder.  If the head is in the corner there is nothing you can do.

I know that's not necessarily the answer you were hoping for, but I'm sure what you want is my truthful opinion. I wish I could give you better news.