Thanks for all the lovely comments about JB & for all the other photos of your beautiful cats.
Taz - here is a quick overview of the differences between Maine Coons & Siberians.
Both MCs & Sibs were developed in cold, harsh environments – MCs in NE USA & Sibs in Russia particularly the St Petersburg & Moscow regions (not really Siberia). They have many similarities – long coats, tufted feet, tufted ears, strong heavy bodies.
MCs are the larger of the two breeds. The biggest differences are found in the head, Siberians should have rounded heads, slightly domed foreheads, rounded cheekbones & no obvious muzzle.
MC heads are much squarer & should have a pronounced square muzzle. (see photos below)
I hope you can see Maine Coon Grand Champion Mabalakat Flash Harry's muzzle here

Here Maine Coon Grand Premier Mabalakat Georgiabrown shows her muzzle from the side.
As JB is only a baby his head is still developing so is difficult to compare at the moment.

Fox, Siberian cat is JB's dad. His head is more rounded, although in this photo he is very alert & has his whiskers forward & the whisker pads puffed up. You can see most of his lovely bottle brush tail. He is a golden tabby & a very handsome boy.
The Siberian coat is much denser & softer, MCs should have a long flowing outer coat over a dense undercoat. The Siberian tail is like a bottle brush whereas the MC's is longer again with a whispy outer coat.
The typical Siberian expression is slightly sad & wistful due to their eyeset, MC's eyes are more oval.

Pushkin a Siberian cat shows the wistful expression beautifully & also the dense, soft coat.
Mcs come in all colours but never coloupoint (think of a Siamese cat) whereas the Siberians have a sister breed called the Neva Masquerade which comes in all colourpoint varieties like Pushkin who is a seal tabby point.
Personality wise MCs are the gentle, laid-back, giants of the cat world. Siberians tend to be a bit more active. Both breeds are very sociable with both humans & other cats.
Another very similar breed is the Norwegian Forest Cat - but that is another lesson :wink: