I went for a cruise along the Adelaide River, on the way to Kakadu, one of several in the area that have “wild’ crocodiles leaping to be fed and took a few pics. They may be wild, but as soon as they heard the boat coming they slid into the water and came over for a feed, so they certainly associate the engine noise with an easy meal. I hope they can tell the difference between a large boat and a small tinny, because they are larger than some of the tinnys people were using for fishing from !