Inside Snake Behaviour with Lisa Gonsalves

When we look at snakes, we rarely think of them as individuals with personalities. Instead, they become a singular group of animals that is dangerous and out to get us. In earlier conversations with Gerry Martin, we explored how far from reality these notions are, yet they continue to persist. More than any other animal, we view snakes through a lens of fear, superstition, and misconception, turning their very presence into omens. What we’ve forgotten is that snakes are animals surviving, evolving, and experiencing this world, just like the rest of us.

If we can replace our fear with curiosity, the lives of snakes reveal a world we are only just beginning to uncover. What drives their behaviours and choices?

Lisa Gonsalves has long been fascinated by animal behaviour, and her work with snakes at The Liana Trust showed her just how much we are yet to understand. In this interview, she shares her observations of their behaviour, decision-making abilities, and the idiosyncrasies that remind us they are far more complex than we often assume. Is it possible that we have imposed a predictability on these creatures, or have we simply never looked closely enough to see how unique and beautiful their journey through evolution has been?

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Hi Lisa, could you tell us a little about yourself, the work you do at The Liana Trust, and how it all began for you?

Hello! I have always loved animals and wanted a career where I could work hands-on with them. I first came to The Liana Trust as a volunteer in September 2018 and was supposed to stay for just three months. But I fell in love with the space and the animals, ended up staying, and eventually asked Gerry for a job!

Today, I am the Curator at The Liana Trust Serpentarium*. I primarily look after the well-being of the snakes housed in the serpentarium, as well as the other animals on the farm. I also oversee much of our venom production, including venom extraction, processing, and handover for the production of antivenom. Alongside this, I have a strong interest in snake behaviour research.

Lisa, along with Sandhya, the Community Liaison at The Liana Trust, attempts to take a snake out of the roof of someone’s home in Ratnapuri, Hunsur (Photo 1). Among the animals that Lisa works with is Bob (Photo 2), a Philippine sailfin dragon. Brought to India to be someone’s exotic pet, he arrived at Liana in terrible condition and was terrified of humans. Sitting with him, helping him become habituated, and feeding him grubs has become one of Lisa's favourite things to do.

Cover Photo: People and snakes sharing the same space.

All photos are courtesy of The Liana Trust.

Gerry spoke to us in detail about snake venom, antivenom, and the interactions between snakes and people, which got us thinking more about snake behaviour. Most of us grow up believing that everything snakes do is purely instinctive. Is that really the case?

I think instinct does play a huge role. But I also think snakes are constantly perceiving and learning about their environments. I have seen this with snakes in captivity over the years, watching how much the snakes we have now have settled down since we first got them and how much they have learned over time.

A lot of them now know what the feeding tongs mean, what the feeding basket looks like, and have even learnt to readily accept pre-killed prey. In fact, a lot of them have learnt that the prey isn't alive and so don't bother with envenomating it. They simply proceed to eat what is offered to them. This is just one instance where some associative learning happens. They have gotten habituated and aren’t necessarily agitated by our presence in their enclosures. This shift happens surprisingly quickly. With new snakes, as soon as we enter their enclosure, they either retreat into their hides or become defensive. Usually within a month, or even less, they understand that we are not a threat. They stay on their basking platform or somewhere exposed while we work in their enclosures. I think this is quite significant for an adult, wild-caught snake to learn so fast!

They also know and remember what they don't like. For instance, when a snake is unwell, we need to inspect it in restraining tubes for treatment, and now they recognise the restraining tube. Depending on their personalities, they either avoid it or strike at it.

If you think about how snakes sense and experience their environment, how do vision, sound, vibration, scent and heat shape the way they experience the world, and maybe even their behaviour?

I think it depends on the species. Some are much more visual than others. Recently, one of our veterinary advisers, Dr. Taksa Vasaruchapong from the Thai Red Cross, came down and was telling me about Russell's vipers. He mentioned these heat-sensitive sacs, which I hadn't really thought about before: what’s called a supranasal sac, located in the nasal area, that allows them to perceive heat from warm-blooded prey. I imagine this would be hugely beneficial in their typical sit-and-wait type of hunting strategy. That completely changed how I think they perceive the world, because I'd always assumed they relied more on vision. But they're also detecting heat, which is really interesting.

There's still so much we don't know. Every species is different, and what works for one may not work for another. We're still figuring out how different snakes perceive their environment and which senses they rely on most. There's a lot left to learn.

It is so interesting to hear you talk about "personalities." It is easy to think that all kraits behave one way and all Russell's vipers another. What kinds of individual personalities have you come across?

We periodically extract venom from the snakes we have at the serpentarium, and most snakes are fairly unproblematic to work with. But there is one snake that stands out. 

She is a Russell's viper coded DaRuKa06. We also call her Hissy Fit because every time we walk by or get even a little close, she starts hissing and will not stop. Sometimes she even goes into a defensive coil, and we still haven’t been able to extract venom from her. We’ve had her since she was very young, and we don't think she has had any traumatic experiences.

There is also another Russell's viper from Kundapura that we have never gotten venom from because he simply never yields. He just doesn't want to bite; he keeps his fangs folded in. If we're able to get a bite from him, he yields little to no venom.

Feeding on a rat in its outdoor enclosure, DaRuKa11, a Russell’s viper at the Serpentarium.

So how much of a snake’s behaviour is shaped by what’s happening around it, and how much comes from past experience? Have you observed instances where snakes make active decisions?

They are responding to their immediate environment, but they are also drawing on what they have experienced in the past. That influences them to act in a particular way in a given situation. So there is learning, spatial awareness, memory, and retention, which lasts much longer than I expected.

When we were tracking Russell's vipers in the field, they would choose whether to flee or stay put, and I think that was an active decision based on their surroundings - how close they were to a hide/ shelter, how exposed they were, how close we'd gotten to them.

You also see it when it comes to feeding. Sometimes a snake simply doesn't want to eat. It'll just sit there while the mouse runs over it, and I think that's a conscious decision not to feed at that moment.

I've seen something similar with baby Malabar pit vipers that caudal lure. They will lure almost immediately with the specific movement or sight of their prey. This is something we are still studying, though.

So I do think snakes are constantly making decisions about how to react to different situations and different kinds of stimuli.

What do you think determines whether a snake decides to flee or stay put? Do you think some of that also depends on the other person or animal and what they're doing?

I'd say it depends on how much opportunity it has to get out of the situation. If it can remove itself quickly and safely, I imagine it would choose to leave. But if it feels it's safer going unnoticed, it may stay still instead. As I was saying earlier, Russell's vipers rely heavily on camouflage. If it thinks it hasn't been detected, staying perfectly still is probably the better strategy. I also think that if there's a burrow or some other secure retreat nearby, that might influence its decision as well. 

I do think the behaviour of another animal can definitely influence how a snake responds. I'm thinking of videos of puff adders where porcupines were practically walking all over them, and the snakes stayed put because they clearly didn't see that as the moment to react.

Malabar pit vipers, like CrMlKa09 here, are ambush predators that pay close attention to their microhabitats. Blending in with orchids in its enclosure at the Serpentarium, this individual may remain motionless for days, even weeks, before deciding to move.

If you had to imagine a day in the life of a snake, what do you think it would look like?

Honestly, I wish I knew. I can tell you what we observe in captivity, and I would like to think that what they do in the wild is this and more.

They’ll often stay in or around a single area, in a few choice spots throughout the day. You don’t see them expending too much energy unless they’re on the hunt for food.

When it comes to hunting, it probably varies depending on the species. An ambush predator might spend a lot of its time sitting and waiting. An active predator would be moving through different spaces, trying to suss out where food is available. The sight or scent of potential predators or prey might influence how they choose these spots in the wild.

Take the Malabar pit viper, for example. They are ambush predators that rely heavily on camouflage, so site selection is very important. They need to find a place where they blend into the background and can go undetected, primarily by their own predators, like a wandering king cobra. They also would factor in what suits them in that microenvironment: temperature, humidity, shelter, etc. They would choose a spot that's close enough to their safe place that they aren't exposed for too long, but where the likelihood of finding prey is high. For instance, if they largely feed on frogs, they might prefer to stay closer to a water body. Depending on the size or availability of frogs or other prey, they may hunt lower down or higher up. During the breeding season, though, I feel like they throw a lot of this out the window while in search of a mate.

There must be so much activity happening around a wild snake. While I believe they spend a major chunk of their time resting, I wonder what all they observe and choose to respond to. I hope to find out somehow.

What do we know about how snakes interact with one another?

What we know is that snakes do interact with one another, but they are not highly social. There is some parental behaviour documented in rattlesnakes, where they guard dens with their young. We have seen nest-guarding behaviours in our spectacled cobras and kraits. There is also some evidence of resource guarding in a species of kukri snake, where they actively chased away other snakes from nests of turtle eggs that they were consuming. 

Beyond that, they majorly interact during the breeding season, where two or more males combat and then engage in a range of courtship behaviours with the females. Snakes can also share spaces like basking platforms or hides, though that may not necessarily count as an interaction - they’re just choosing the most favourable spot.

Gerry Martin chimes in: I think when we talk about social behaviour in snakes, it is often difficult for us to assess because snakes don't give us the signs we expect to see. They have fixed faces, their eyes don’t blink, and they don’t have limbs to gesture with. So I feel that our approach to behavioral science isn’t yet equipped to decode what is happening. 

But there is research, like Lisa mentioned, on rattlesnakes. The same study found that rattlesnakes often spent more time with their own family members than with others. And when the neonate snakes were first born, there was always a female snake basking with them.

Ten years ago, I wouldn't have thought twice about why so many sea kraits gather in one spot on the beach when there are so many seemingly similar places around. Why do they all congregate? We need to start asking more questions, even about snakes we think we already know so much about.

Basking under a light in its indoor enclosure at the Serpentarium, EcCaKa08, a saw-scaled viper carries out an essential activity in its daily life.

What do you think human presence feels like from a snake’s perspective?

I feel that, based on the kind of interactions they’ve had with humans, they may have altered perspectives and responses. Snakes born and bred in captivity haven’t been subjected to anything too adverse from humans. They don’t react as defensively or show the same flight response as wild snakes, despite the innate instinct to recognise something bigger as a threat and get away from it.

Alternatively, snakes that have grown up around human habitation encounter people often, and those encounters are almost always negative. We’ve seen many snakes come in with scars and injuries. So their association with humans may be quite bleak.

Then there are the monocled cobras in Bardhwan district, West Bengal, which, for generations, have not been chased away or killed on sight, as the people associate them with the goddess Jhankeswari. Those cobras are apparently very calm, move commonly through houses and walking paths, and don't even hood up around people.

When you're working so closely with snakes every day, how do you tell what they're experiencing? What are the signs that they're stressed, defensive, or even in pain?

For an uncomfortable, scared, or potentially defensive snake, the first sign I notice is a slight retreat. Even if they are already in a safe space, like inside a hide, you will find them tucking their heads in or curling their bodies up a little tighter. Some may rear their heads back if they are preparing to strike. Then come the more obvious displays, from hissing and tail wagging to inflating their body or, in the case of spectacled cobras, spreading their hood.

I also feel they turn to look at you, and you see their pupils shift. They are noticing you and are locked in on you at that moment. And if you watch carefully, even while they are displaying, there are brief moments when they stop. I feel like if, at that point, you step back and give them space, they will move away.

For some injuries, like broken bones, blisters, or open wounds, if you touch or manipulate the injured area, they may twitch or attempt to bite. I recognise that as a sign they are experiencing pain.

But when they are unwell due to bacteria or parasites, you often don’t notice until they start showing clinical signs, like when they stop eating altogether, or you begin to see mucus coming from their nostrils. By then, things have already progressed to a more severe stage, and they have probably been in pain or discomfort for a while.

Treating an unwell Russell's viper at the Serpentarium.

How do you think human activity has changed the way snakes behave in the wild?

Snakes can learn and alter their behaviour in response to changes in their environment. The threat humans pose has caused snakes to modify their behaviour simply to survive in landscapes that are largely human-dominated. In undisturbed areas, their behaviour would probably be different, but you still wouldn’t see snakes fully exposed all the time because they have other predators. Snakes are ectothermic, so they still prefer places where temperatures are more constant for their own comfort. I imagine they would spend much of their time in hides, only coming out to hunt or thermoregulate.

Gerry chimes in: There are examples of snakes changing from being diurnal to nocturnal. In places that are completely undisturbed by humans, you’ll see checkered keelbacks active and exposed during the daytime. But in busy agricultural landscapes, you will often find them moving around only at night.

Humans can introduce many changes into the lives of snakes. Depending on the activity, it might decrease or increase the abundance of certain prey species. Like many other animals, snakes have to adapt. By and large, the species we see persisting in human-dominated landscapes are the adaptable ones, like cobras and rat snakes. Many specialist snakes don’t do well around people. Once we change the landscape around them, it no longer provides what they need, and they disappear. Around cities today, the diversity of animals, not just snakes, has vanished.

As a Russell’s viper moves through its home range, women working in the fields often find themselves in close proximity to these snakes.

After all this time in the field and at the serpentarium, what is one question you still wish you had an answer to?

I think the thing I most want to know is actually quite simple: what snakes do through the year, or over the years, as they grow from neonates into adulthood. I want to know where saw-scaled vipers and Malabar pit vipers go during the dry season. What are they feeding on? What triggers them to become active again? What cues tell them the monsoon is about to arrive? How is the changing climate affecting their behaviour? 

With the Malabar pit vipers, I think we may have part of an answer. One of our Malabar pit vipers went missing for a while this summer. We checked all the boundaries of the enclosure to make sure they were secure. I was hoping he hadn’t squeezed himself out. 

Weeks went by, and during a mildly desperate strip search of the enclosure, we found him sitting under a rock in one corner of the enclosure. I suppose that, through the dry season, when it gets so warm and dry, that's simply one place that’s comfortable for them.

If someone young is reading this and interested in snakes, what would you tell them? Is this still an emerging field?

It absolutely is. You don't have to tackle the biggest questions in the universe.

In fact, this is something I think a lot about while reading Gordon Burghardt, who has done incredible work on reptile and snake behaviour. He studies intelligence and perception, but even then, it's hard to talk about snakes as a whole because everything is so species-specific. You have to ask what certain species do in certain situations.

Very often, especially in India, there's still so much basic information we don't know. Even something as simple as care sheets for native species often doesn't exist, while you'll find extensive care sheets for non-native corn snakes, milk snakes, and other species that are common in the pet trade.

Honestly, if we could just follow snakes around with a video camera or just spend some time observing them instead of either shooing them away or immediately attempting to catch them (a big pet peeve of mine with herp folks), that alone would teach us so much. There's still so much we see every day that remains unexplained.

We're still a long way from understanding many snake species, or even knowing when different species can be grouped together. There's a huge amount of work left to do.

If you're interested in this field, that's exciting because there are still so many unanswered questions. And if you're looking for someone to read, I'd highly recommend Gordon Burghardt. He's incredible and has done some fantastic work on this.

Preparing an enclosure for a Malabar pit viper with Assistant Curators Shivaani and Hajeera.

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*The Liana Trust Serpentarium primarily focuses on providing high-quality venom, free of cost, to researchers and antivenom manufacturers, provided that they follow WHO standards for processing. The main motivation behind offering venom free of cost is to decommercialize and deprivatize venom production, reduce costs, and improve the quality, efficacy, and accessibility of antivenom.

All requests for venom, as well as its extraction, processing, and handover, are carried out with permission from and in close collaboration with the Karnataka Forest Department.

Through the serpentarium, they also conduct behavioural and ecological research by maintaining snakes in long-term captivity and continually refining husbandry practices for the species in their care, including the Big Four, Malabar pit vipers, hump-nosed pit vipers, and king cobras.

To know more about Lisa’s work and The Liana Trust, you can visit their website: https://www.thelianatrust.org/

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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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