Human influence on the wariness of Melanosuchus niger and Caiman crocodilus in cuyabeno, Ecuador

The effect of mark-recapture experiments on the wariness of Caiman crocodilus and Melanosuchus niger in two lakes in Amazonian Ecuador was examined. Three experiments were conducted with five, seven, and 10 sampling replicates, respectively. Each sampling replicate consisted of one nocturnal spotlight count around the lake, during which caimans were captured, marked, and released. There were negative correlations between the number of individuals seen in each sampling replicate and sampling replicate sequence in both lakes and both species. In one lake, there was a positive correlation between the percentage of wary caimans and the sequence of sampling replicates. Our findings indicate that observation and capture, even if harmless, affect the spatial distribution and wariness of crocodilian populations.