I've had them bust out of a Havahart 1080. The beaver bent the weak metal trigger hook and blew out every one of the cheap J-clips Havahart uses on that otherwise stout cage. Fatslinger warned me that that would happen but I didn't listen. Kirk D. reckons if your cage is less than 16" tall a beaver can hunch up and bust out. Beaver don't bust out of Koro traps but they are expensive and I worry about clueless urbanites finding mine and getting an arm, leg, or jaw broken when they set it off. Other than the potential for busting out, cage traps work well on land. I add castor to the bait sticks with some peeled for eye appeal. Beaver love cottonwood branches and I think apple slices would work also.