Effects of Phylogeny, Stratum and Season on the Diel Activity Patterns of Mammals in a Lowland (…)

ABSTRACT

We studied the diel activity patterns of 35 species and three genera of terrestrial, arboreal and semi-arboreal mammals in the lowland rainforest of the Conkouati-Douli National Park, Republic of Congo, deploying 38 camera traps on the ground and 21 in the canopy during more than a year. Activity patterns varied highly between species. However, as expected, patterns appeared to be fairly similar within several taxonomic groups, for example, strictly nocturnal in Anomaluridae (scaly-tailed ‘squirrels’) and Lorisoidea (galagos and relatives), or mainly diurnal in Sciuridae (true squirrels) and Simiiformes (simians). As predicted on the basis of microclimatic considerations, activity tended to occur at more variable times in terrestrial species than in arboreal species. Despite the heavy rainfalls occurring during the rainy season, observed species did not show a general trend to be active at more variable times during the rainy season than the dry season. Finally, as a probable consequence of their habit of resting in trees at night, most semi-arboreal Simiiformes were found to exhibit an enhanced activity after sunrise and before sunset in the canopy. The possible effects of other (and possibly confounding) factors such as body mass and seasonal fluctuations in food availability are discussed.