Does cold weather have any effect on them?
Apparently in Aliens vs. Predators, it doesn't.
Maybe because there aren't that many people in the North and South Poles? "I'll be back!" The Terminator
hahaa
They're big iguanas, it makes sense.
Presumably they're from a planet a bit hotter than Earth. If you wanted to spend your vacation on a nice hunting trip, you don't go someplace 200 degrees cooler than you like, it's just no fun.