There are two important things to know about tracking wild elephants, and it's better to learn both of them before you're actually in the jungle, tracking wild elephants. First, elephants are fast. In thick forest in this case, the vast Ulu Masen ecosystem in the Indonesian province of Aceh, where leeches writhe beneath your feet and white-handed gibbons hoot from the treetops they can outpace even deer. Second, elephants can't climb trees. This is good, because that's precisely what you're meant to do if one of them charges.