Not to be a downer, but I'm going to disagree and say they're just Domestic Long Hairs (or DLH for short). I'd say 95% of all "Maine Coon mixes" have no Main Coon in them at all. They are a very popular breed right now (the current Persian or Siamese), so it's not impossible for there to be a handful of mixes out there. But for the most part, cats advertised as "MC mixes" are probably just long haired mixed breed cats of no particular ancestry. The hallmark of a Main Coon is not ear tufts, toe tufts, or a thick mane, almost all long haired cats have those, but their impressive stature. Main Coons are massive, generally 20lbs + at maturity without being the least bit fat. They are also, due to their current popularity, very prone to certain health problems, especially heart disease. We have a family that has several Maine Coons from breeders at work, and we see them on average 1.5 times a month. Their youngest two came from the breeder with ringworm, which took forever to clear, and one of their cats has severe allergies to what seems like everything in our area and they recently thought he might have intestinal cancer (turned out he didn't, but they even went to a specialist two hours away and were going to have a biopsy done to rule it out). He's absolutely gorgeous, but a real mess health wise.
