There are few hidden mickeys on the jungle cruise. the first one is on the crash landed air plane ( can only mean one thing. thats right hippos) it is on the side of the plane it is three rings that form a mickey head. the other one is very hard to see and took me weeks of seeing it a hundred times a day, it is on the exit of the temple, it is on the left side and is made of wall molding and shadowing. its very hard to see. OH and also, its not a hidden mickey, its a hidden MINNEY!
They've added the one on the plain just so that the Jungle could have a visable HM from the boats. The actual "official" HM is found inside one of the rock rooms (can't remember which one) but was at a hard to get spot, barely visable to even CMs. The "hidden minnie" I think is just coincidence, because I've had several keys tours on my boat before, all pointing it out and every time, I still can't see it, and they all say it's not official, but it's there. Also, take a closer look at the heads of the three canoes on Pygmy Beach ;)