Common Iguana Behaviors and Their Meanings

Iguanas use a range of head bobs, dewlap movement and positioning, torso compression, gait and other movements to communicate. Figuring out what your iguana is saying to you or someone else can make the difference in how you respond to an encounter…and it’s fascinating to be able to understand what another species is saying.

First, a recap of basic behaviours. Behaviours can be roughly grouped into the following categories:

Personal Defence

This is typically exhibited when the lizard feels threatened by a predator. In the wild, this may be snakes, caiman, and various birds and mammals. In captivity, until the iguana feels comfortable in its new home, defensive behaviours are exhibited towards humans, cats, dogs and large objects of unknown intent (garbage trucks, school buses, a previously accepted human wearing a hat or aposematic colors, etc.)

Defensive behaviors include:

  • Dewlap flares
  • Raising up on all four legs and laterally compressing the torso
  • Dorsal crest rigidity
  • Side presentation
  • Tail whipping.

If the perceived threat doesn’t back off, open-mouth gaping and click-hissing may be used as the iguana backs away or tries to circle around the threat.

Territorial Defense, Attempted Acquisition/Expansion

Iguanas, especially males, are highly territorial. In the wild, the more dominant males carve out territories into which they will not allow other males. Males will allow females to pass through or spend time in their territory. This probably has probably proven to enhance that male breeding success: let the ladies hang out to bask and eat, and they’ll likely be back during the week or so that they are receptive to mating.

Young males and those not yet strong or tough enough to displace an established male from his territory hang out on the fringes of the area. Some of these males are called pseudo females: not only do they not yet have the secondary sex characteristics associated with the well-developed dominant males of the same age (larger jowls, “brain bumps”, adult coloring and markings, breeding season colors), their pheromones mimic that of females so that dominant male will ignore them or not pursue too heavily when they come too close.

Behaviors associated with territorial defense or attempting to oust an established male in order to take over a new or additional territory include:

  • Dewlap flares
  • Raising up on all four legs and laterally compressing the torso
  • Dorsal crest rigidity
  • Side presentation
  • Tail lashing.

When on the ground, locomotion will be by crab-walking – moving forward and back sideways, as they maintain their side presentation towards their target.

By now you’ve figured out that Territorial Defense/Acquisition and Personal Defense behaviors look quite a bit alike. Fortunately, iguanas are smart enough to tell the difference between when they should use one or the other – or when they are seeing another iguana doing one or the other.

Since humans are at least as smart as iguanas, they, too, will be able to figure out if their iguana is defending itself or has decided to claim your side of the bed as its preferred sleeping place.

Social Status – Challenging, Defending, and Signaling Submission

It will come as no surprise that the behaviors identified with Challenging and Defending social status look a lot like Personal Defense and Territorial Defense/Acquisition. There is one difference, however: Challenger and Defender will often meet head-on, snout to snout. Their heads will be lowered while their bodies often remain hunched up and laterally compressed, their dorsal crest rigid and tail base lifted off the ground. They will face each other, possibly crab-walking while pivoting on the point between their noses, as each tries to get the other to back off.

When one of the iguanas gets the upper nose, so to speak, and is able to approach the other iguana who is presented sideways towards him, the iguana will butt his nose up against the sideways iguana, butting against the ribs and working up to the shoulders and neck. During this time, the sideways iguana is generally trying to get turned around to go nose to nose again, or get to the other one’s side, or, deciding that those who run live to fight another day, get the hell out of there. If no such openings present themselves, the iguana who has realized he doesn’t have a chance has one more option: acknowledge the other iguana’s dominant status by submitting.

Submission posture in iguanas is very much like that in dogs. The torso and tail are pressed flat against the ground, as is the head and neck.

The flattened iguana will stay there, trying not to move away, while the dominant iguana noses him, possibly biting the skin of the neck or nuchal crest and chewing on or shaking it.

The dominant iguana may even climb on the submissive one while retaining hold of the skin of the neck, looking very much like the mating position of a male on a female.

Once the dominant iguana feels his point has been made, he will walk off, or he will detach himself (if he has been biting) and step back, allowing the submissive one to slouch-walk away.

Let’s now discuss the most common iguana behaviors in more detail.

Why Does an Iguana Bob it’s Head?

Iguana head bobbing

Iguana head bobbing is a captivating behavior that’s fascinating to observe. Yet, it is so much more than just an adorable quirk. It’s a vital part of their communication and social interaction. These charismatic lizards bob their heads to convey a wide range of messages, and understanding them can help us to build a better bond with our scale-clad buddies.

Generally, an iguana’s head bobbing can be seen as a form of ‘reptile talk’. Depending on the speed, rhythm, and frequency, this behavior can indicate anything from a friendly greeting to a display of dominance or even an expression of annoyance.

Type 1: Greeting, Thanking, and Relaxed Head Bobbing

When your iguana bobs its head up and down in a slow, rhythmic manner, it’s not just listening to an internal beat; it’s communicating with you. This type of bobbing, often characterized by a smooth and leisurely pace, is usually a positive sign. It’s like your iguana is giving you a friendly nod of acknowledgment, saying “hey there, pal!”

A study has found that this head bob is a common social signal amongst iguanas, suggesting a relaxed state or a cordial interaction with others. So if you see your iguana doing the friendly bob, it’s likely they’re content and at ease with their environment.

Type 2: Head Bobbing to Show Dominance

The ‘bobbing dance’ as I affectionately call it, is quite common in iguanas, and it’s all about dominance! Picture it: one moment your iguana is sitting calmly on its favorite perch, and the next, it’s bobbing its head up and down like it’s listening to some inaudible iguana rock anthem.

This form of head bobbing is not your iguana jamming to unheard tunes, but a display of their assertiveness. These rhythmic head movements are a way iguanas communicate their dominance to other iguanas or even their reflections! That’s right, iguanas are so territorial that they may even try to assert their dominance over their own reflections.

Dominance bobbing typically involves a series of rapid vertical bobs, followed by slower ones. It’s almost like watching a quirky dance routine.

When you notice your iguana displaying this bobbing behavior, the best course of action is to give it some space. Your pet is essentially saying, “This is my territory. Respect it.” Encroaching on its space during this display might stress your pet. So, it’s best to wait until your iguana calms down.

Type 3: Aggressive Head Bobbing

Aggressive head bobbing in iguanas is quite distinctive. Unlike the rhythmic, smooth movement of a greeting or dominance bob, an aggressive bob tends to be quicker, and more abrupt and may be coupled with other signs of aggression such as puffing up their body, hissing, or even tail whipping. This bobbing can be triggered by various factors such as feeling threatened, territorial disputes, or sometimes just plain grumpiness.

The key to dealing with this behavior is recognizing the warning signs early. If your iguana starts to exhibit these signs, it’s best to give them some space. Trying to handle them during this time could lead to stress for them and potentially a nasty bite or tail whip for you.

Type 4: Twitching Head Bobs

The “Twitching Head Bob” is a clear signal from your iguana saying ‘no touching’ and ‘leave me alone’.

Now picture this: the head bobbing is rather quick and seems a little jerky, almost as if your iguana is impatiently tapping its foot, but with its head. It’s like they’re mirroring the way you might rapidly nod your head to say “No, thank you!” to an extra helping of a dish that you don’t particularly like. It’s a firm, assertive statement, but not quite aggressive.

You might notice your iguana demonstrating this behavior when it’s not in the mood for interaction, maybe after a long day of basking, or when it’s feeling a little under the weather. Understanding and respecting this signal is essential to maintaining a harmonious relationship with your pet.

So, how should you respond when your iguana breaks into a twitching head bob? The key is to respect their space. Just as we all need a little alone time now and then, your iguana is no different. If you spot this type of head bob, it’s best to refrain from touching or handling your pet for the time being. Give them the space they need, and you’ll find they’ll be back to their usual, sociable selves before long.

Type 5: Breeding Head Bobs

Breeding season can turn your usually calm and composed iguana into a bobbing superstar, and it’s all part of their natural mating ritual. The rhythm and pattern of these bobs are noticeably different – they’re slower, deliberate, and can be coupled with dewlap extensions to attract the opposite sex. Imagine a suave guy at a bar, nodding to the beat of a slow song, that’s your iguana right there, wooing its potential mate.

Now, why does this happen? It’s all about attracting a partner and establishing dominance. The intensity and frequency of these head bobs are a signal of their virility and readiness to mate. It’s their way of saying, “Hey, look at me, I’m strong and ready for some love!”

Licking/Tongue Tasting: What Does it Mean When Your Iguana Licks You?


Picture your iguana, standing tall, flicking out its long, forked tongue to explore its surroundings. It’s an iconic image, but have you ever wondered what’s going on? Licking in iguanas is quite similar to us humans using our hands to feel our surroundings.

Iguanas have an extraordinary organ known as the Jacobson’s organ located in the roof of their mouths. This organ, together with their tongues, is a powerhouse of sensory information. When your iguana flicks out its tongue, it’s collecting tiny particles from the air, your skin, or other objects. These particles are then transferred to the Jacobson’s organ for analysis. It’s kind of like their super-sleuth way of figuring out who or what’s in their environment.

So, when your iguana licks you, they’re not trying to give you a sloppy kiss but getting to know you at a chemical level. Fascinating, isn’t it?

Iguana Hissing: Why Does My Iguana Hisses at Me?


Hissing in iguanas can be a bit alarming if you’re not expecting it. It’s a sound that grabs our attention. But for iguanas, it’s a natural way of communicating discomfort or fear.

When an iguana feels threatened or stressed, it might let out a hiss as a warning. It’s their way of saying, “Back off! I’m not comfortable with this!” This kind of vocalization is essential for them in the wild where standing their ground against predators or rivals is a matter of survival.

As an iguana owner, understanding and respecting this signal is crucial. If your iguana hisses at you, it’s not because it dislikes you. It might just need some space or time to adjust to a new situation. Always respond with patience and give your iguana the space it needs.

Dominating Position – Territorial Behavior

In the wild, iguanas are solitary creatures, each with their own territory to guard. They have a range of behaviors to communicate their dominance and defend their space. One such display is the “dominating position.” In this stance, an iguana will stand tall, puff up its body, and extend its dewlap (that’s the flap of skin under its neck). It’s like they’re saying, “Look at me, I’m big and tough! This is my territory!”

In a pet setting, this behavior can be a response to seeing their reflection in a mirror or window, or it can be a sign they feel their space is being invaded. If your iguana takes this posture, it’s essential to respect its boundaries and give it space.

Eye-Closing: Why Does My Iguana Close its Eyes?


Eye-closing in iguanas can be a very endearing behavior. When an iguana closes its eyes in your presence, it’s often a sign of trust. They feel secure enough around you to let down their guard. Imagine that – a wild creature with instincts honed for survival, feeling safe in your company. That’s a real privilege. It’s the equivalent of a warm, fuzzy hug from your pet iguana. As an iguana owner, it’s one of the most rewarding signs that you’ve built a strong, positive bond with your pet.

Iguana Bulging Eyes


At first glance, bulging eyes in iguanas can look a bit alarming. But, rest assured, it’s a normal part of their behavior. Iguanas will often bulge their eyes to adjust to different light levels, similar to us squinting when we walk into bright sunlight. They may also do this when they’re feeling particularly alert or are simply stretching their eye muscles. Although it may look strange to us, for them, it’s just another part of being an iguana.

Sneezing: Why Is My Iguana Sneezing?


If you’ve been startled by a sudden sneeze from your iguana, you’re not alone! I still remember the first time my own iguana, Ziggy, let out a sneeze – I jumped, and then immediately worried if he was coming down with a cold.

The truth is, unlike in humans, sneezing in iguanas is not typically a sign of illness. Iguanas are unique creatures that have developed a rather intriguing mechanism to expel excess salts from their bodies. They do this by “sneezing” out a saline solution, a process scientifically known as ‘salt excretion’. Isn’t that amazing?

Here’s a fun fact: You might notice a white, powdery residue around your iguana’s nostrils. This is simply dried salt from their sneezes. Nothing to worry about, but it’s always a good idea to keep their habitat clean.

Of course, if you notice excessive sneezing or other signs of discomfort in your pet, it’s always a good idea to consult a vet.

Why Is My Iguana Turning Black?

Iguanas have the remarkable ability to change their skin color for various reasons, much like chameleons. One common reason is temperature regulation. If your iguana is cold, it may darken its skin to absorb more heat. Quite the survival tactic, right?

However, a change in color can also be a sign of stress or illness. If your iguana is consistently dark, it might be trying to tell you something is wrong. Look for additional signs of distress such as reduced appetite, lethargy, or changes in their normal behavior.

When in doubt, always consult a professional. Remember, while we love our iguanas and know them well, a veterinarian can provide crucial insights and recommendations for their health and well-being.

Why is My Iguana Standing Up?

Have you ever seen your iguana rise on its legs, extending its body in a striking upward pose? This behavior, often called “standing up”, can be quite a sight to see!

In the wild, iguanas stand up as a defensive gesture to make themselves appear larger and more intimidating to potential threats. However, in captivity, your iguana might display this behavior for a variety of reasons. It could be feeling threatened or stressed, or it might just be curious, trying to get a better view of its surroundings. Remember, each iguana is unique and will have its own patterns of behavior!

Tail Wagging: Why Do Iguanas Wag Their Tails?

Now, let’s talk about an iguana behavior that might remind you of a different kind of pet – tail wagging. Yes, just like dogs, iguanas wag their tails too!

Unlike dogs, however, an iguana wagging its tail can signify a wide range of emotions. It could be a sign of irritation, a warning, or even a show of dominance. In some cases, tail wagging might precede a whip-like lash out if your iguana is feeling particularly threatened. The key here is to observe the context in which the tail wagging occurs to accurately understand its meaning.

Mouth Opening: Why Does My Iguana Open its Mouth?

When your iguana opens its mouth, it could be for several reasons.

One of the most common reasons is thermoregulation, as iguanas often open their mouths to release heat. However, a gaping mouth can also be a sign of a respiratory issue or an impending bite if they feel threatened. Just as with the other behaviors, your own experience with your iguana will help you interpret this behavior accurately.

How to Tell if an Iguana is Angry?

Iguanas, much like us humans, have a range of emotions, and yes, they can get quite grumpy! If your iguana is showing signs of being upset, it’s important to give them some space. This could mean they’re feeling threatened, stressed, or just plain moody. Now, how can you tell if your iguana is angry?

The key signs include puffing up their bodies, whipping their tails, and hissing. If your iguana is puffing up, it’s usually a way for them to make themselves look larger to scare off a perceived threat (could be you if you’ve startled them!).

Tail whipping is another defensive behavior. It can be quite powerful, so keep a safe distance! And if they’re hissing, it’s definitely a sign they’re not in a happy place.

These behaviors can take a toll on their health if they’re in this state frequently, as the stress can weaken their immune system and make them more prone to illness. So, if your pet iguana is consistently showing signs of anger, it might be a good time to reassess their living conditions or even seek advice from a vet.

What Does a Relaxed Iguana Look Like?

On a brighter note, a content and relaxed iguana is a joy to be around! Relaxed iguanas have a calm demeanor, and you might notice they are less reactive to your presence. Their bodies will be loose and flexible, and their eyes will remain at a normal size.

A very relaxed iguana may even close their eyes in your presence – a big sign of trust! This might be after a delicious meal, during a good basking session, or even while you’re gently stroking their head – ahh, the life of a spoilt iguana!

Just like us after a spa day, a relaxed iguana is a healthier iguana. Stress is a big no-no for their health, while a chill-out iguana can better fight off illness and enjoy their delicious greens more.

The Digging Dilemma: Why is My Iguana Digging?

Green Iguana Digging

Just like a dog scratching at the door, your iguana’s digging habit may seem puzzling at first, but it’s actually one of their unique ways of expressing their needs, especially when it comes to their reproductive behavior.

When it comes to digging, you may find your iguana turning into a veritable miniature bulldozer, especially if it’s a female during the breeding season. Let’s try to understand this behavior a bit better.

From the corner of your eye, you might see your pet iguana scraping and clawing at the base of its enclosure. This is no casual activity; your iguana is in full-on construction mode! With persistence and concentration, it carves out depressions or burrows, often working in the same area repeatedly. You might find it using both its front and hind legs, rotating between them as it works to create the perfect excavation.

Now, you might be wondering, why does my iguana suddenly fancy itself as an architect? Well, in the wild, female iguanas dig burrows for laying their eggs – it’s their natural nesting behavior. Even in captivity, this instinct doesn’t fade away.

When your iguana starts showing signs of restlessness, increased activity, or a particular interest in one corner of their enclosure, it’s likely that your female iguana is gravid, meaning carrying eggs. The digging behavior is her preparing a safe, comfortable space for her eggs.

Remember, though, not all digging is associated with reproductive behavior. Iguanas are naturally curious creatures and might also dig out of boredom or a need for exercise.

Circling Walk: Why is My Iguana Walking in Circles?

This is an example of a somewhat relaxed circle walk. Spike is walking in a circle around (we see towards the end of the clip) the LuvDoll. Note the more relaxed position of the limbs and dewlap. He even stops to taste the floor.

Iguana Circle Walk

Iguana Circling Crab Walk

Here both forward and sideways movement is being used in order to get farther away and circle around the object being warned off or checked out.

Iguana Circling Crab Walk

Iguna Ritualized Walk

Note the forward locomotion with the tail lashing, lateral compression, and flared dewlap. This may be used when a threat from some outside agency (human, dog, another ig) is perceived. It is essentially “big lizard” in motion.

Iguana Ritualized Walk Part 1

Here are wonderful examples of the leaning iguanas will do when the perceived threat is above them. You can see Spike lean way over to the right as he moves around trying to keep the sideways presentation towards the perceived threat. As a side note, some iguanas will lean into your hand when you are petting them, often leaning so far over and so blissed out by the attention that if you remove your hand, the iguanas will fall right over.

Iguana Ritualized Walk Part 2
Iguna Ritualized Walk Part 3

Iguana Investigative Walk

Used when exploring a new environment, or an old one which has had some new scents laid down, such as when strangers (human, iguana, or other animals) visit. Note the positioning of the legs: they are bent in the normal walking mode rather than straightened and stiff as in ritualized modes. Note also the tongue touching the floor, used to transfer sent more directly to the vomeronasal organ.

Iguna investigative Walk

Iguana Challenge/Attack Walk

Here the walk starts out like a Ritualized Walk but with less tail lashing. The object being approached is in sight, and the iguana is figuring out the best way to approach it. You can see where he turns and heads directly for the object, in this case cameraman Steve holding the LuvDoll (his version of the LuvSock).

Iguna Challenge or Attack Walk Part 1

Here is an interesting combination walk that illustrates how tonguing the floor (or another iguana) is not always a benign activity associated with smelling. A male will challenge another male by tonguing the other male’s neck; it is a sort of insult, perhaps comparable to how a human may objectify another human as a way of depersonalizing the other person. In this walk example, Spike has his eye on someone (Steve): he bobs, tongues the floor, and proceeds to walk around towards Steve, speeding up as if to attack, then going into a sideways presentation with the increased lateral compression and straightening of the legs.

Iguana Challenge or Atatck Walk Part 2

The Direct Approach Walk of Iguanas

Spike takes a more direct approach to LuvDoll after circling just enough so that he has a straight shot for the neck. He bobs a bit of the Multi-Purpose Bob, and then heads for the neck. We can’t see exactly what he’s doing, but based on head and neck movement, it appears he is butting or tonguing the LuvDoll. Done to a male iguana, this is definitely an aggressive action. Done to a female, it can be mildly aggressive or checking to see if she’s amenable to being courted.

Iguana The Direct Approach Walk

Iguana Bites

Note how Spike has hold of the LuvDoll to try to hold it in place while he looks for the right place to bite, working up and around the torso a bit to bite on the dorsal crest. This behavior is quite common both in breeding season when the male works up to the female’s neck, and males biting other males. It is much harder to get one’s mouth around the side of the torso of a comparably sized competitor, so they go for the neck or anywhere along the dorsal crest.

Iguana Bite Part 1

Here we have a great example of the circling walk that ends in a bite to the haunch of the target. As with The Bite I, this may be directed to a female or to a male. In this particular case, since the LuvDoll isn’t moving, a sign of receptivity (or, at least, of “I’m thinking about it…”) in females, and Spike goes for the haunch rather than the neck, it appears he is treating the LuvDoll as a male competitor.

Iguana Bite Part 2

Here Spike is biting the LuvDoll. When one male attacks another, the iguana being bitten tries to get away while the biter tries to hang on and wrestle the other iguana into submission. This is different than mating in that in mating, a receptive female remains rather still, or walks slowly, during intromission. True, the LuvDoll is moving on the uncarpeted floor, but Spike is rather more vigorous in his leg movements than he would be during intromission.

Iguana Bite Part 3

Here is another example of why a torso bite isn’t particularly effective on a similarly-sized iguana. Spike bites but doesn’t get much despite the give in the terrycloth LuvDoll. He apparently doesn’t think much of the taste, either, as he works it through his mouth. This video has a very good picture of the tightened muscles underlying the nuchal and dorsal ridge – note the ridge extending up from the neck and back, which act to increase the height of the spikes, making the iguana look taller and more threatening.

Iguana The Direct Approach Walk

Filled under: Lizards

Leave a Reply

Your email address will not be published. Required fields are marked *