Temperature influences the activity patterns of armadillo species in a large neotropical wetland

Abstract

In this study, we characterized the activity patterns and estimated the activity overlap between two armadillo species (Dasypus novemcinctus and Euphractus sexcinctus) in the Pantanal wetlands of Brazil. We report the effect of daily mean ambient temperature on activity onset and duration of these armadillos. We captured seven yellow armadillos and three nine-banded armadillos and fitted them with very high frequency radios and temperature loggers. By monitoring the temperature of the environment (air temperatures and burrow temperatures), we inferred when the armadillo was active (above ground) or inactive (inside the burrow). Yellow armadillos were active mainly during the daytime and in the beginning of the night, while nine-banded armadillos were active mainly during the night. However, nine-banded armadillos presented a bimodal activity pattern, becoming active for a short period in the middle of the morning and/or afternoon. The proportion of activity overlap was 0.28 between the species, occurring primarily at the beginning of the night. At lower temperatures, yellow armadillos tended to leave their burrows earlier and were active for longer periods. This is probably an adaptation to their physiological constraints and limited thermoregulatory capabilities. Xenarthrans could be used as models to obtain valuable information about how physiology affects mammal behavior.