Patronen in de tekening van de gladde slang

Variation in markings of Smooth Snake Each individual Smooth Snake (Coronella austriaca) can be recognised by its unique pattern of dark spots and stripes running from the head down the back. German publications indicated that some patterns were less common than others, and even rare. Observations in the Netherlands suggest regional variation in the patterning. Individuals are sometimes heavily patterned, with patches rather than spots. Sometimes the spots merge to become stripes running lengthwise.The crown, the characteristic marking on the head, is not always confined to the head but may have one or two spurs running down the back. For example, the smooth snakes in the Veluwe in the centre of the country has less distinct markings than those in other parts of the Netherlands. In order to get an overview of this variation, people were asked to send in their photos for comparison. The frequency of occurrence of certain patterns and the heaviness of the markings was recorded for each individual. Comparisons madebetween snakes in Noord-Brabant in the south and the Veluwe. A total of 221 photos showed that there were significantly more snakes on the Veluwe (44%) with less distinct markings than in the province of Noord-Brabant (8%). Moreover, a striped rather than spotted pattern, through spots merging lengthwise, is often seen. However, it is rare in some places (Veluwe 2%) and common in others (Noord-Brabant 25%). Also a pattern in which the crown has one or two spurs running down the back is no exception, but is found muchless in Noord-Brabant (6%) than on the Veluwe (17%).