What on Earth is a Pala Polonga?

Hello everyone! Today I would like to talk about the amazing Sri Lankan pit viper (Trimeresurus trigonocephalus), also known locally as the Pala Polonga. These beautiful snakes are endemic to Sri Lanka, which is in south Asia, and are commonly found in the wet zone grassland and rainforest areas. 

These snakes are green with a black tail tip and a black line along their heads from the nose to the back of the jaw line (these are also known as temporal lines). Most Pala Polongas also have a black variegated pattern along the length of their bodies. Their green and black pattern along with their unique shade of green reminds many people of mint chocolate chip ice cream. Maybe we should skip dessert this time! They also have a loreal pit on each side of their head between the nostril and eye. This pit is the external opening to an extremely sensitive infrared detecting organ allowing them to “see” temperatures and strike prey accurately even in the dark! That would probably give them an unfair advantage if they ever decided to play a game of hide and seek! They use these pit sensors to locate and catch animals like lizards, frogs, small mammals, and birds. Sri Lankan pit vipers are arboreal with short prehensile tails that help them hold on to tree branches to keep them from falling, aid in climbing, and help them “anchor” themselves when catching prey.

Another cool fact about the Pala Polonga is that they are sexually dimorphic. That means both genders exhibit different characteristics that allow us to identify the gender simply by looking at them. There are two distinct physical characteristics that help us identify their gender. Let us go over them together! The first characteristic is size. The males of this species usually stop growing once they have reached a length of 24–30 inches. The females of this species are a bit larger, growing up to 51 inches in length. That means some females can grow twice the length of some of the males! Wow! Another way to tell them apart is by color. I know, we already talked about how they are a green snake, but the males have more of a blue tint while the females are more of a green tint.

Like most pit vipers, the Pala Polonga is viviparous, which means the babies develop inside of the female and she gives birth to live, fully formed baby snakes instead of laying eggs. In the wild, they usually give birth around June or July and have litters of 5 to 25 babies! Even though this species is not highly defensive or territorial, they are venomous and use their hollow fangs to inject hemotoxic venom into their prey. Hemotoxic venom is a type of venom that negatively affects red blood cells which causes hemolysis, disrupts blood clotting, and attacks types of cells and tissues that can lead to tissue damage and possible organ failure.

Thank you for your time! I hope you found these snakes as interesting as I do! Please don’t forget to stop by Scaly Slimy Spectacular and see these beautiful snakes in person on your next visit! I don’t know about you, but I’m craving a scoop of mint chocolate chip now… at least the edible non-venomous kind anyway!

Sam J.
Keeper III, Herpetology