Daily activity patterns of the Atlantic bamboo rat (Kannabateomys amblyonyx) in southern Brazil

Abstract

Several biotic and abiotic factors influence on daily cycles and mammalian life-history patterns. In this paper, we investigated behavioral patterns and diurnal and nocturnal activity of the Atlantic bamboo rat Kannabateomys amblyonyx (Rodentia, Echimyidae) an endemic species of the Brazilian Atlantic Forest. We conducted the study in the southern portion of the species distribution, in patches of an introduced bamboo species (Bambusa tuldoides) that occurred inside native forest areas. We evaluated behavior and activity time of the individuals by conducting scans during nocturnal and diurnal periods (mean scan length – 24 min, range from 2 to 30 min). We considered the following behavioral categories: feeding, moving, self-cleaning and resting. We did not find significant difference between the diurnal and nocturnal activity (randomized MANOVA, SS = 0.07, d.f. = 45, P = 0.59). The Atlantic Bamboo Rat seemed to be active during the entire 24-h daily period, but with activity peaks by the beginning of the night (between 19:00 and 21:00). The low energy quality provided by food (buds, twigs and bamboo leaves) should compel the rodent to eat several times a day in order to supply their metabolic needs. Besides that, predator activity both during day and night, as well as other local environmental characteristics, probably represents relevant factors that influence the 24-h activity patterns of the studied rodent.

Key words: behavior, activity period, circadian cycle, Kannabateomyx amblyonyx.