Species Saturday

Species Saturday #15 – the very green Asian vine snake

Saying hello to sssssssspecies Saturday # – the Asian vine snake or the Oriental whipsnake, Ahaetulla prasina

Perfect head shot of Ahaetulla ©OuTrop

As most people know, snakes are long, legless, carnivorous reptiles. Like all scaled reptiles (known as squamates), snakes are ectothermic (where body heat relies on the temperature of the environment – internal physiological sources of heat are of small or negligible importance), vertebrates (have a spine) covered in overlapping scales. Within the suborder Serpentes, they different from legless lizards as snakes have no eyelids nor external ears. Snakes are currently found on almost every continent (except Antarctica, some small islands and large islands, such as Ireland and New Zealand). 

This snake, the Asian vine snake (Ahaetulla prasina) is a regular visitor to camp. We see this species a lot as we walk through the forest and sometimes very close to home. I personally woke up and in a blurry half-asleep state, began to take some dry laundry off the line. What should appear on the line and under various socks but this skinny little beast, looking exactly like the green rope my washing was on. At this time in the morning, a snake so close to your face is quite a shock! Thank fully they are only mildly venomous and can only bite you one the skin in between your fingers as due to their small size. 

Another Bornean vine snake… ©OuTrop

Adults of this species may attain a length of around 1.8 m (6 feet), with a tail .6 m (2 feet) long (yes snakes do have distinct tails!). The species that we see here in Borneo looks a lot like those of South American, perhaps showing some elements of convergent evolution. Like most snakes in the area, Ahaetulla prasina feeds on small reptiles and amphibians, particularly lizards and tree frogs which are very numerous (especially right now in the wet season!). This species, like a lot of snake species, have a remarkable range… Ahaetulla prasina can be seen in India, Burma, Thailand, Malaysia, Singapore, China, Indonesia (including our Bornean site), Bangladesh, Cambodia, Laos and Vietnam… Snakes are either venomous, swallow prey alive or kill by constricted prey to death. Most snakes are not venomous, and those that are primarily use it to kill and subdue prey, not for for self-defense. 

Image source and credit here

Snakes are one of those awesome groups which can be very big and very small. The extinct Titanoboa cerrejonensis snakes have been found up to 12–15 m (39–49 ft) in length. Now a-days the largest snakes (alive today) are the reticulated python and the anaconda. We get anaconda here in Borneo (once in the camp kitchen!) which measures about 7.5 m (25 ft) long. This species is considered the heaviest snake on Earth. You can compare this to the smallest snake on the planet, the Leptotyphlops carlae, with a length of about 10 cm. Snakes use smell to track their prey. They smell by using their forked tongues to collect airborne particles, then passing them to a specific organ in the mouth and act on what they smell. Snakes have a forked tongue to provide a directional sense of smell and taste simultaneously. The constant motion of the tongues sample particles from the air, ground, and water, analyzing the chemicals to determine the presence of prey or predators near by. The Asian vine snake, the whole genus Ahaetulla are particularly special snakes as they  have binocular vision. Both their eyes capable of focusing on the same point at the same time. As with all snakes, they also rely on sensing other animals approaching by detecting faint vibrations in the air and on the ground. Here is an image from OuTrop staff member – a prefect example of snake prey … and a perfect example of prey larger than the predators head! 

Join us next Saturday for a great species run down. Do keep in touch via info@outrop.com!

Thea Powell

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