Going inside the cage
Because the door to the enclosure was open, he looked inside to see if he could discern anything about the objects that were being held inside. He did this to see if he could learn anything about what was being held there. It is likely that a beaver or a group of groundhogs that were looking for a house utilised the cage as a home base while they were looking for a new location to dwell.
Alternatively, the cage may have been used by humans. Jim’s thoughts were racing with a myriad of outcomes and strategies that may be taken in response to the situation. When all was said and done, it turned out to be nothing at all like to that at all. As Jim processed what he was seeing, a shiver of fear spread throughout his body and down his spine.