Voici la réponse "officielle"

. Reste à savoir si "dragon" est en fait une traduction convenable pour désigner Phayanak...
Thank you for your email and I apologize for the delay in getting back to you.
The birth certificate is based on our Chantharakhati calendar or Thai Lunar Calendar where the waxing moons and wanning moons differ from one year to another. For 2011, our new year started (per Thai Lunar Calendar) on Nov. 26, 2011, so by the date Romy was born, it was waxing moon 7, month 2. For the year, the big snake represents our Thai year and is NOT the same as Chinese calendar where it would be considered as the dragon.
In Thai lunar calendar, the big snake refers to "Phayanak", which is a mythical big snake that lives in the
Mekong River. Its shape is like a snake, huge in size but the head is like a cobra with spikes, etc. You may look up the pictures on google by typing in this word "phaya nak."
So, to answer your question, the birth certificate follows Thai lunar calendar and not of the Chinese calendar, so don't worry. All information is correct as she was born in
Thailand and this is the same how we all Thais have.