I've always believed that animals understand when they're being helped. You don't need to be the same breed or life form to understand being in distress, and in that moment when he starts untangling the lights and the deer sees that he's not reaching out to touch it or harm it, I don't think there's any question that the deer understands what's happening. There have been a bunch of whale rescue type videos where whales have approached boats, seemingly to get help from tangled fishing nets, and they cooperate with people until they're free and then they go about their merry way. I once helped a duck stuck in fishing line at a lake and had a similar experience. When I walked up to the duck, it panicked and flopped around trying to get away, so I waited until it calmed down and saw that I wasn't there to eat it, then I went to work cutting the line and it stayed calm the whole time. Then I let it go and it casually walked over to the water and swam away. As humans we've lost sight of the fact that even though we're an advanced race, we are still just mammals and the rest of the mammals out there aren't as dumb as we like to think they are.
SHARPEN IT LIKE YOU LOVE IT, USE IT LIKE YOU HATE IT