Take a wolf and a dog and mate them. A given gene will have 1 wolf copy and 1 dog copy. This is a 50% wolf. Cross a pair of 50% wolves and you can call the offspring 50% wolf, but that same one gene may end up with a double dose of wolf genetics or a double dose of dog genetics, or 50/50 each. This means a '2nd generation' 50% wolf can end up being more than or less than 50%. Often the less scrupulous breeders will pass off the offspring that are very wolfish as 100% wolf and the more doglike ones as 50% wolf. You then have people who interact with a very low-wolf-content animal and it seems like a dog. They hear it is 50% wolf and think that all 50% wolf creatures will be like that. They then get their own 50% wolf which may be a first generation cross or may be a high-wolf-content 2nd or 3rd generation cross, and the animal is uncontrollable, and ends up being abandoned or destroyed.
