I think in the case of those stupid rats they are becoming endangered because they just lost life's lotto. Apparently they only have 2 or 3 babies once or twice a year. That doesn't sound like a very good survival strategy for a rodent on the bottom of the food chain if you ask me. Man may be helping them along a bit but they don't really need much help there. Most of the animals that lived on this planet are already extinct and a lot of them got that way long before man was here. Those rats sound like one of the stragglers. Perhaps we could catch the remaining ones and give them to 5 year olds who want hamsters and their breeding success will improve.