The hidden existence of a sub-adult Smooth Snake Sub-adults of the Smooth Snake (Coronella austriaca) are seldom seen, having an even more secretive existence than the adults. Thus, little is known about their length and weight, the distances they travel and about where to find them. To find out more, monitoring was carried out for ten years in two small remnants of raised bog in the southern province of North Brabant; in one of these, artificial shelters were set out to attract any snakes present. We were able to distinguish an individual by the unique marking just behind the head. In this way, fifteen individuals were identified among the twenty-seven found. Due to the artificial shelters, there was a marked difference between the two areas in the number of snakes found, fourteen sub-adults being found in the area with them, and only one where shelters were absent. Seven sub-adults were found several times within one season, always on the same spot. Two of the snakes were caught as adults five years after first discovering them as sub-adult. These were the only snakes not found at their original location, although at 125 metres, not so far away. Another discovery was of what seems to be a hibernaculum: for several years in October, one or two sub-adults were found on the same spot.