Eastern coyotes are allegedly hybridized with Canadian wolves and run larger than the typical western version. They also have stronger jaws and bigger chompers. Most of the few I've seen look like they'd go at least 40 pounds or so, maybe more. In the South, they also cross with red wolves. There's also the coydog crosses, also larger than the Western ones. I watched a program on Netflix that detailed the evolution of the new, improved Eastern breed.
I've also read that the Eastern ones are smarter and harder to hunt, but don't know that for a fact.
The only hybridization I recall reading about between coyotes and wolves were with the issue of red wolves. Some where trying to claim they were a hybrid and therefore not able to be listed as an endangered species. Do you have any links? The hybrid angle for eastern coyotes would be an interesting read.
I bet the size difference is due as much to amount of food available as anything.
