Hey, this year my husband shot a huge bull elk right through the lungs. It ran off after the shot and did not leave one spot of blood. We looked everywhere! We circled back to where he shot it and started looking around instead of down for blood and the bull was with in 30 yards of where he shot him. He had only bled about 4 inches down his body from the entrance wound. When we cut into him, he was completely filled with internal blood. So don't give up! I have seen it go both ways....found some, lost some, but don't give up. Good luck!!!