Understanding Snake Venom with Gerry Martin
- Chetana B P
- 6 hours ago
- 7 min read
I first met Gerry Martin in 2003, when I was about 13 years old. He was an educator at the first nature camp I had ever attended, and, without exaggeration, that one week I spent exploring nature with children my age under Gerry’s guidance changed the course of my life.
All these years later, Gerry remains a dear friend, a mentor, and the first person I turn to when I want to learn more about the lives of snakes. He is an internationally renowned herpetologist and conservationist whose career spans three decades. His friends and family, however, also know him as an expert barbecuer, a spelling bee champion, a caring gardener, and a remarkably brisk walker.
One evening, during one of my visits to his farm, I sat down with him by the lake to learn more about venom, snakebites, and people’s perception of snakes.
Hello Gerry! For those who are not familiar with your work, could you tell us a little bit about The Liana Trust and the main areas you focus on?
Hi, Chetana. At The Liana Trust, our focus is on human-snake conflict mitigation and management. What we're trying to do is create a model at the district and state level for how we address the human-snake issue.
We are working on understanding snakebites by looking at the sociological, socioeconomic, psychological, and ecological aspects, while also trying to figure out how we can enable better management of venomous snakebite by building capacity within various relevant departments, such as the forest department and the health department. We also enable research on snakebite treatment and provide venom free of charge for the production of antivenom.
Cover image: For Gerry, conservation has always been about people as much as wildlife. Whether he’s in the field, engaging with communities, or advancing venom research, every step is part of a larger mission to help people and snakes coexist more safely. Photo: The Liana Trust
Let us start at the beginning. What is venom, and how is it different from poison?
The difference is that a poison can be anything that you imbibe, breathe in, or absorb through your skin. It could be natural or synthesised. Venom is a protein created inside an animal and needs to be injected into the prey or victim for it to take effect.
Tell us about snake venom. What is it made of? How do snakes produce it? Where do they store it?
Venom is a lot like saliva, and it is usually pretty species-specific. It also contains all kinds of different proteins and acids, and it is quite complicated—much too complicated for me to even understand!
Venom is produced in a gland, much like our salivary glands, and in snakes, the venom gland is located on the rear side of the head. From there, it goes into a sac, where it is stored, and then there is a duct that leads from there to whichever kind of fang actually delivers the venom.
When we talk about venom, my understanding is that it has evolved independently across a number of animal groups. Are there similarities between the venoms of these different groups, or can calling them all “venom” be a little misleading? Say, if we are talking about fish or cone snail venom?
Venom evolution is fascinating, and there are some folks around the world doing some very interesting research on it. But yes, venom has evolved multiple times throughout evolutionary history, and not from a common ancestor. Still, calling all these animals venomous is pretty accurate.
Snake venom, scorpion venom, and cone snail venom, although structurally different, are functionally sort of similar. They are proteins that are produced inside an animal and injected for a definite purpose, and many of them have very similar effects on their victims—prey or attackers.
What does venom do to a living organism once it has been injected into it?
So, it does different things to different organisms. By and large, snake venom can be categorised into three groups. There's hemotoxic venom, which affects the blood and some tissues. There's neurotoxic venom, which affects the nervous system, and cytotoxic venom, which affects tissues at a cellular level.
Depending on what venom has been injected, it could cause blood to either clot or prevent it from clotting. It could also cause haemorrhaging, and all of this would be the result of hemotoxic venom. If it's neurotoxic venom, it could shut down or block the transmission or reception of nerve signals. If it’s cytotoxic venom, it could cause immense tissue damage.
Of all the venomous animals in the world, snakes seem to occupy our minds the most, whether out of fascination or fear. Are snakes dangerous to humans?
That is a very difficult question to answer. India loses almost 60,000 people to venomous snakebites every year, and at least twice that number suffer a permanent loss of function or some disability. So yes, this is an issue.
But individual snakes, in my opinion, are not dangerous. They are no more dangerous than a person driving from Bangalore to Mysore. In fact, we lose about 173,000 people every year to road accidents in India.
The fact that an animal is venomous doesn't make it dangerous in itself. Snakes do not see humans as food, nor do they compete with us for the same resources. So I would say that these are all accidents, and we can avoid them quite easily.
(1) Indian python (Python molurus), photographed in a patch of streamside forest in Devala; (2) Ashok's bronzeback (Dendrelaphis ashoki), found inside an Adivasi school in Gudalur; and (3) Indian wolf snake (Lycodon aulicus), encountered along a trail in Devala. Despite their reputation, snakes are not aggressive; they are defensive animals that prefer to avoid people whenever possible. Most snake species, like the three pictured above, are also non-venomous: of the roughly 4,000 known snake species worldwide, only about 15% are venomous, and an even smaller proportion have venom capable of causing serious harm to humans. Photos: Samuel John
Sometimes venomous snakes choose not to inject venom when they bite, right? What do you think shapes that decision?
I wish I knew…
One thing we know is that venom in snakes did not evolve as a defense mechanism. But for an animal without limbs, the only thing it can do is bite. So they do bite, but what they really need their venom for, and this is completely speculative, is to subdue their prey, and they would not want to waste it.
So very often in defensive bites, especially in elapid species like cobras and kraits, they don't seem to inject venom, or they inject very little. I've also personally seen two Russell's viper bites that have been sublethal, and I also know of a Russell's viper bite in which no venom was injected.
You hear more reports like this, and so, by and large, snakes don't want to bite. They can also moderate how much venom they inject, unlike some other animals, where venom release depends on how much pressure is put on their spines or stingers.
Snakes have muscles surrounding their venom sacs, which they use to compress and squeeze venom out. And I think they are pretty good at holding it in, otherwise it would be flowing everywhere!
So, a venomous snake is not necessarily an aggressive snake?
Aggression basically means that someone throws the first punch. There are snakes that are defensive—actively defensive—and some are very good at defending themselves. But no snake will needlessly attack.
I believe very strongly that there is no such thing as an aggressive snake.
You said that India loses around 60,000 people to venomous snakebites every year. Could you tell us more about this?
We're actually just about beginning to scrape the surface on that at the moment.
Around where we live, within a five- or six-kilometer radius, we needed to talk to snakebite survivors for a focus group discussion assessing the psychological impacts of snakebite. Within two weeks, we found more than 30 people, and since then, our list has grown to almost 80 people who have survived snakebites. Almost all of those bites were from Russell’s vipers found in this area.
I think the numbers don't give us enough texture. But yes, the prevalence of snakebite in rural agricultural areas like this is quite high. I still feel that this is something that we can actually change. There are other places as well where snakebites are even more common than they are here, and it is often because of the practices that people follow. I think that's where we need to change things.
From your experience living and working in rural Karnataka, how do farmers perceive snakes? Are they aware of the benefits of having snakes in their fields, or is it a risk they would rather not take?
Before coming here and starting our work, I thought that there was only fear.
But when you see how real the risk of snakebite is here, I think saying that people are just afraid is actually quite a big disservice to them. At the same time, I think agricultural communities are doing themselves a disservice by not trying to differentiate between different snakes.
Very often, we're called to help remove snakes that are around someone’s home. If it's a non-venomous snake, our immediate response is to say that it is non-venomous and that there's no need to move it at all. Still, many people want us to take it away.
We try to tell them that having non-venomous snakes around is a good thing. It is very difficult to convince people, but we do manage to get through to some, and fortunately, that number is increasing.
It starts to get dark, and Gerry takes a break to answer an important phone call. He never misses one. Then he heads into the kitchen to light the grill. Our conversation continues as the grill heats up, and Gerry patiently answers the many questions I have about antivenom.
Come back to this space for Part Two in this series.
To know more about Gerry’s work and The Liana Trust, you can visit their website: https://www.thelianatrust.org/
About the author
Chetana is a wildlife biologist, ocean explorer and educator. Dogs love her almost as much as she loves them.
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