Are brown vine snakes venomous?

Brown vine snakes, also known as the brown treesnake or night tiger, are a species of colubrid snake found in South and Southeast Asia. They are relatively small, growing to around 1 meter (3 feet) in length, and are notable for their ability to glide between trees by flattening their bodies. But one of the most frequently asked questions about brown vine snakes is – are they venomous?

The Short Answer

No, brown vine snakes are not venomous. They are non-venomous colubrid snakes that hunt small prey like lizards, frogs, and birds using constriction rather than venom. While they do have enlarged teeth at the back of their jaws, these are not connected to venom glands and are used solely to grip prey. So brown vine snakes pose no danger from venom to humans.

Brown Vine Snake Taxonomy

To fully understand why brown vine snakes are non-venomous, it helps to look at their taxonomy or scientific classification:

• Kingdom: Animalia
• Phylum: Chordata
• Class: Reptilia
• Order: Squamata
• Family: Colubridae
• Genus: Ahaetulla
• Species: Ahaetulla nasuta (brown vine snake)

As members of the family Colubridae, brown vine snakes are in the largest snake family consisting mostly of non-venomous species. This is in contrast to venomous snake families like Elapidae (cobras, mambas) and Viperidae (vipers, rattlesnakes).

Colubrid Snake Venom

While most colubrid snakes are non-venomous, there are some exceptions. Certain genera like boomslangs and vine snakes in the Colubridae family do possess venom glands and enlarged rear fangs. However, brown vine snakes specifically have not evolved these venom delivery adaptations.

Enlarged teeth at the back of a colubrid snake’s jaws are not indicative of venom capabilities on their own. These teeth function primarily to grip slippery prey like frogs and lizards. So the presence of these teeth does not mean a snake is venomous.

Hunting and Diet

Instead of venom, brown vine snakes rely on constriction to subdue prey. Their diet consists mainly of:

• Lizards
• Frogs
• Small birds
• Rodents
• Bats

Brown vine snakes are arboreal, meaning they spend most of their time in trees and bushes. Their excellent climbing abilities and binocular vision help them hunt prey among branches. They strike quickly to seize prey in their mouths, then wrap their bodies around victims to constrict them.

Self-Defense

While not venomous, brown vine snakes do have some self-defense adaptations. These include:

• Camouflage – their brown and green coloration helps them blend into tree bark and foliage to avoid predators.
• Mimicry – by flattening their neck and head, they can mimic the shape of venomous kraits.
• Musking – they can release a foul smelling musk from their cloaca to deter predators.
• Biting – they have sharp teeth and can inflict a painful bite, even if it’s non-venomous.

Some individuals may exhibit an aggressive defensive display, including hissing, neck-flattening, and striking. But this is mostly bluffing behavior.

Brown Vine Snake Venom Myths

Despite their lack of venom glands and fangs, myths and misinformation still persist around whether brown vine snakes are venomous. Some common false claims include:

• “They’re rear-fanged venomous snakes” – Rear fangs alone do not indicate venomous capability.
• “Their saliva contains toxins” – There is no evidence of toxic saliva.
• “They can spit venom” – No snake can actively spit venom.
• “They carry harmful bacteria in their mouths” – Their mouth bacteria is no worse than any other snake species.

These kinds of myths seem to originate from people misunderstanding photos of brown vine snakes gaping open-mouthed, which they often do when hunting or startled. Overall, there is no reliable evidence that brown vine snakes possess any kind of medically significant venom.

Bite Treatment

On the rare chance a brown vine snake does bite a human, here are some guidelines for treatment:

• Wash the bite area with soap and water.
• Apply an antiseptic cream if available.
• Monitor for signs of infection – redness, swelling, pus.
• Seek medical attention if infection develops.
• DO NOT attempt to cut or suck out venom – there is no venom to remove.
• DO NOT use tourniquets, ice, electroshock, or venom extractors.

In most cases, a brown vine snake bite simply requires basic first aid and monitoring. There is no specific anti-venom required as they are not venomous. Seek prompt medical care if the wound shows signs of worsening infection.

Are Related Vine Snakes Venomous?

Brown vine snakes belong to the genus Ahaetulla, which contains 8 total species found in Asia. Here is a summary of venom capabilities for related vine snakes:

As this summary shows, only the Malayan and Sri Lankan vine snakes are known to be venomous within this genus. The venom potency is mild and unlikely to cause human fatalities. But the other Ahaetulla vine snakes, including the brown vine snake, are non-venomous.

Venom Differences Between Snakes

It’s understandable to be cautious around any unfamiliar snake species. However, it’s also important not to assume all snakes are equally venomous – there are major differences between venomous and non-venomous species.

Factors that indicate a highly venomous snake include:

• Fangs – Long, hinged hollow fangs connected to venom glands.
• Elliptical pupils – Venomous snakes tend to have vertical slit pupils.
• Triangular heads – Allow for larger venom glands.
• Heat-sensing pits – Help locate warm-blooded prey.
• High venom toxicity – Capable of causing human injury or death.

Brown vine snakes lack all these dangerous adaptations. They have short teeth, round pupils, small heads, no heat-sensing pits, and no venom glands whatsover. So they can be easily distinguished from hazardous venomous snake species.

Conclusion

In summary, while brown vine snakes do have some distinct physical features like large rear teeth, they are completely non-venomous. They lack venom glands and fangs, instead relying on constriction to subdue prey. Myths about their alleged venomous status are not backed by any scientific evidence. So brown vine snakes pose no toxic hazard to humans. However, as with any wild animal, they should still be treated cautiously and not handled unnecessarily.