1983 2 February at lunch Ned Fetcher told me of seeing a Lachesis muta and scat of Felis onca, so after lunch several of us went after them. Walked out the Camino Circular Circano to the Camino Central, all the way across the Sendero El Swampo, and N. on Holdidge Trail to its origin, w/out finding either. Did see clear F. onca tracks in mud near water in the swamp. Found the scat at Holdridge 500, and the Lachesis at Sendero-El Swampo 750, in both cases right at the signs. The scat was in midtrail, and had many bugs; no associated tracks. The snake was 4-5m south of the trail, against a log parallel to the trail. Two logs intersected this one from upslope from the trail, so that the snake was in a "box canyon" of logs. This is in good, fairly open forest, among palms 6/m high. Snake was opaque, and in a slightly longitudinal resting coil, w/head on one end. After several minutes of photos, it moved its head slightly. When I dribbled some red paint on its neck from a jar tied to a pole, it assumed a more erect, striking pose and moved its head slightly in my direction. Impression was that it was alert and prepared to be defensive, but not aggressive. We left it