It is difficult to identify Thai snakes
Of Chiang Mai’s 50+ snake species I have seen 13 at Dokmai Garden. Whenever I encounter a new snake, it takes quite an effort to make a proper identification. Although the number of snake species is conveniently limited, as compared with the estimated 2500 species of wild plants in the immediate neighbourhood, the short glimpse you get of a snake and the individual variation still keeps you in a cloud of mystery as to its identity and potential danger.
I certainly understand the 18th century explorers who shot and killed birds and snakes, at a time when there were hardly no books, no teachers, no bird call CD:s. You had to sit down and discover the morphological details, the basis for writing books and becoming an experienced naturalist.
Today the situation is different; walking next to an experienced field biologist will save you tremendous amounts of time. For birds and bird calls, I am grateful for my friendship with Tony Ball. For snakes, I treasure my friendship with Sjon Hauser. He has spent years studying road kills and living snakes to get a fair view of northern Thai species and their variation, also discovering new species. Hopefully he will summarize his vast knowledge in a book.
Below are two pictures of the same keelback species (Xenochrophis flavipunctatus) :
Of diagnostic value are the two ‘Pierrot tears’, hardly seen in any other northern Thai snake species. The black chevron behind its head is another important feature. Previously, this species was considered a colour variety of the chequered keelback (X. piscator), but that species is less chequered and has indistinct Pierrot tears and no chevron.
Believe it or not, this is the same species, caught in the same garden in Chiang Mai. This individual displays the black edges of the ventral scales, another distinctive characteristic. The yellow colour of the ventral scales is not specific and may be much paler. It should not be considered dangerous, but an interesting inhabitant of your monsoon garden.
An English name? It should have been ‘chequered keelback’ but that name is connected with the other original species. ‘Variable keelback’ would be a good name but is quite boring. Do you have any suggestions?
Text: Eric Danell
Identification: Sjon Hauser
Photo: Ronny Willman