Field observations on the thin-spined porcupine, Chaetomys subspinosus (Rodentia; Echimyidae)

A radio-collared Chaetomys subspinosus was studied in a reserve of montane Atlantic forest in Santa Teresa, Espirito Santo, south-eastern Brazil. The animal was followed during three sampling nights, totalling 17 hours of observation. It was possible to collect data on activity pattern and habitat use through the use of scan sampling at 10-minute intervals. C. subspinosus exhibited an arboreal and strictly nocturnal habit, starting activity around dusk and retiring to a sleeping tree before the sunrise. Overall, it is a lethargic and slow-moving animal, spending most of the night time resting (68 % of scans). Feeding was associated with moving, and these activities occurred in 18 % and 11 % of the scans, respectively. Auto-grooming was observed in the remaining observation time (3 % of scans). C. subspinosus was observed eating only tree leaves, and leaf fragments were the only material found in its faeces as well. These observations suggest that Chaetomys is an nocturnal, arboreal folivore, exhibiting great similarity in habit and habitat use with true erethizontids such as Sphiggurus and Coendou. Although rarely seen, Chaetomys seems to adapt to disturbed habitats throughout its range and its conservation status may be better than previously thought.