My kitty doesn't purr..Is that common?

He is a big (18 lb) Maine Coon, 3.5 yrs old and he doesn't purr. Occasionally when he is on my lap and I am scratching him under his throat and chin and he especially content; I will feel, rather than hear some vibration in that area. I am not concerned, although I do love the sound of a cat purr. He is very vocal, meows, chirps, trills and talks to me ALL the time!
I just wondering if anyone's else's kitty's didnt purr.

Of the four we have in the house, three have rumbly purrs. Punkin, however, has a silent purr, and the only time we hear it is when we pick him up.

I also ahve a cat that rarely purrs. Aya maybe turns on the motor once every other day for 2-3minutes. It's very hard to hear. She's all love and cuddles for those 3 minutes but god help you if you're still petting her when it stops.

I didn't know for sure if my lil tuxy-boy Tex the Tornado could purr... until four months ago.... when suddenly... he let me know he has a motor. He only shares every once in a great while, though.

JoJo is the purr box. Jack is a silent cat... if he's exploring new territory (like when I allow him to explore the deck of my apartment), I get a 'mrrw' from him... he also doesn't purr audibly. I can feel him purr, but never hear him unless he (rarely) lets me put my ear up to his body...

My domestics are purr boxes ... Punky helps me sleep by getting up and purring on me ... My semi ferals do not purr regularly.. In nearly 6 years I have heard Zoey purr three times I think

All of our cats purr, some more loudly than others. Whisper purrs, but we've never heard her. When we pick her up and feel that motor running in her throat, we know she's purring. But it's a very, very quiet purr. Bootser is like her sister with the quiet purr.

Mollipop, however, sounds like a little motorboat. She's got this huge purr coming out of her body....wakes us up in the middle of the night.