You can see what leech leggings look like in this picture. The Forest Service staff were wearing leech leggings that morning too. BTW, screaming does not help get rid of leeches. Just flick them off with your finger if you find them before they find skin; otherwise, use some salt.
Even though it is not jungle, there were still plenty of leeches out after the rain. Anywhere it was shady and had vegetation on the ground, there were leeches. The waterfalls were all in such places. Lucky bought leech leggings (50 baht) and I tucked my pantlegs into my socks. We went to the Tham Yai waterfall, but one rain at the end of the dry season was not enough to start it flowing. We skipped the rest of the waterfalls. It was not worth fighting the leeches to see a dry waterfall.
There are wild elephants on top of Phu Kradung and on the plateau just below the summit. I heard that a monk was killed a few months ago by a wild elephant near the Buddha Image. We never saw anything but their droppings and warning signs to be careful of wild elephants. However, there was one time we could smell a musty, barnyard like smell. I have had similar experiences with bears; it means they were close and probably watching us, even though we could not see them.