THE MOUNTAIN PIT VIPER - Ovophis tonkinensis This is a rare little snake, often found on top of cold mountaintops, after midnight, so you are unlikely to see one out hiking. They have a few names....the Mountain pitviper, mountain viper, Chinese pit viper, spotted pit viper, Arisan habu, Chinese mountain pit viper, and also a Bengali name: পাহাড়ী বোড়া সাপ (Pahari boda sap).
DESCRIPTION - taken from our sister site:
Venomous. Variable in colour and pattern but generally yellow, orange or tan with dark brown or black alternating blotches running the length of the upper back with similar markings along the side. Head is large and tall with small eyes and light stripes running along each side of the jaw. Head is dark similar in colour to a river rock helping with camouflage.
Active at night usually well hidden in rock crevices. The Mountain Pit Viper is an ambush predator that will wait in a single position ready to strike. They are a viper and have relatively long retractable fangs and will bite readily at anything that comes within range when hunting for food, but not actively aggressive when encountered.
Not prone to give chase but will hold their ground if they feel cornered, though will retreat quickly if the opportunity arises. A bite from a Mountain Pit Viper should be considered very serious and medical attention should be sought immediately. Although not known to be deadly serious damage can occur from a bite even if treated and complications can always arise.