Use of highway culverts by the water opossum (Chironectes minimus) in southeastern Brazil

Abstract The water opossum (Chironectes minimus) is a semi-aquatic mammal that is infrequently sampled in Atlantic rainforest areas in Brazil. Here we report on new records of C. minimus in the state of São Paulo, southeastern Brazil, and comment on its behavior and ecology. We placed nine camera traps in culverts and cattle boxes under a highway, between 2017 and 2019. From a total of 6,750 camera-trap-days, we obtained 16 records of C. minimus (0.24 records/100 camera-trap-days) in two cameras placed in culverts over streams. Most of the records were made between May and August, in the dry season and in the first six hours after sunset. The new records are from a highly degraded area with some riparian forests. The records lie approximately 30 km away from the nearest protected area where the species is known to occur. We suggest that C. minimus has some tolerance to degraded habitats, as long as the water bodies and riparian forests are minimally preserved. The new records presented here also fill a distribution gap in western São Paulo state.