Individuals of a Thestylus aurantiurus Yamaguti & Pinto-da-Rocha 2003 population in the Parque Estadual da Serra da Cantareira (São Paulo, SP, Brazil) show an increase of activity throughout the year. This increase is related to the reproductive season of these scorpions, from September to November. The abundance of scorpions was related to environmental factors in four different areas of the park. More scorpions were collected in the higher areas, far away from water sources of the park and not exposed to flooding. A short description of the Thestylus aurantiurus burrows is also presented.