The Battle for Territory: 11 Reasons Why Green Anoles Fight

Green anoles are cute lizards that are quite popular in the reptile trade. Their cute appearance, ease of care, and social behavior have a lot to do with their notoriety. But these lizards are not all fun and games.

Despite being social, generally docile, and friendly, they can sometimes exhibit aggression towards their terrarium mates.

They can’t really hurt each other that much physically, but they will stress one another, leading to weaker immune systems, and we all know where that leads.

So, today we’ll discuss green anoles’ aggression. What fuels it, how do you detect the early signs of violent behavior, and what can you do about it? Let’s jump right in!

Reasons Green Anoles Fight and Show Aggression

If your green anoles display signs of aggression, consider the following explanations:

Protecting Territory

The ideal tank size for a green anole is 20 gallons, although some people go for 10 gallons for a specimen. This is fine, generally speaking, but the tank’s size matters more when housing more than one lizard.

Green anoles can exhibit territorial tendencies, which is typical for all animals, not just lizards. If they don’t have sufficient space, they will begin to fight because of it.

Males are generally more territorial, so they require a lot more space than the minimum recommended.

However, it’s worth noting that males will display aggression and excessive territoriality no matter how much space they have. They are simply hardwired to become violent toward each other.

I recommend sticking to one male per tank, paired with one or more females, depending on your preferences.

Establish Social Dominance

This is a reptile-specific behavior because all social reptiles, and animals in general, live by specific hierarchical rules. Males and females can exhibit this behavior, but it’s more prevalent among males for obvious reasons.

You can usually tell that the anoles are fighting over hierarchy if they engage in scuffles when eating, looking for resting spots, or even during their normal interactions.

Some reptiles might just snap at one of their tankmates if it comes too close, which is a sign of domination behavior. These behaviors are standard in a reptile society, so you shouldn’t seek to correct them, mainly because you can’t. Reptiles will do whatever Mother Nature programmed them to do and will live by their own standards.

Instead, your job should be to monitor your lizards to make sure their hierarchy-based violence remains manageable. Some lizards may be more aggressive than others, in which case you might want to intervene.

Defense of Resources

Green anoles will always fight over food and water if these resources aren’t sufficient for all members.

You can also include space and climbing and hiding areas in the same category, given that these are also resources for them, providing specific benefits. To put it simply, if your lizards starve or don’t have sufficient water, they are far more likely to engage in combat.

Always assess your anoles’ behavior during mealtime and, in general, during their daily interactions. If your anoles fight over food, take this as a sign that they’re not eating enough.

Increase their meal size and frequency and try to feed anoles separately to mitigate their aggression. Anoles are far less likely to fight when living in abundance with plenty of food for everyone.

Also, keep in mind that some anoles will eat more than others. This is due to differences in body composition, age, and social status. Those higher on the hierarchical scale almost eat more and eat first.

Try to circumvent this issue by feeding the low-status lizards separately to make sure they don’t experience nutritional deficiencies.

Fighting Over Breeding Rights

Unfortunately, there’s nothing you can do about this one, nor should you attempt to. Breeding-related fights are not only common among reptiles, but they are necessary.

This is a way for males and females to select their mates based on physical attributes and behavior. Fighting is a great way of differentiating between the lizards in terms of social status, so it is necessary.

However, keep in mind that anole males can be extremely vicious towards one another during the mating season. You should never house more than one male per terrarium during these times because someone is bound to die.

If you’re willing to take the risk, at least consider increasing the tank’s size dramatically and offer a variety of hiding spots to ensure that the loser has a way out of the combat.

Even so, males are unlikely to cooperate or display any tolerance towards other males during the mating process. It’s everyone for himself.


Green anoles require sufficient space to feel safe and comfortable in their habitat. The minimum recommended tank space is 10 gallons, but I think this works better for juveniles.

Adult lizards that get close to 7-8 inches are best kept in 20-gallon habitats, preferably more. If you have more than one lizard, consider going slightly higher than 20 gallons per specimen.

These reptiles might not be too big, but they’re quite demanding in terms of available space. If overcrowded, the anoles will experience stress, become more violent, and eventually face health issues because of it.

Not to mention, an overcrowded tank gets dirty faster and requires more maintenance along the way. The more frequent maintenance sessions will also stress out your anoles, creating a vicious circle that you’re better off avoiding altogether.

Lack of Food

This is the one reason that explains aggression among green anoles better than any other. The typical adult anole requires one meal every other day, and the meal size differs based on the lizard’s age, size, and appetite.

As a general rule, a green anole can consume 3-5 medium-sized insects during one meal. By medium size, I mean that the insect shouldn’t be larger than the distance between the lizard’s eyes.

This metric system applies to all lizards when it comes to figuring out the optimal size of their food items.

However, if your anoles keep fighting over food and appear as if they could eat more, feed them more. Don’t get too fond of the idea of 3-5 insects, as this is just a recommendation, not an absolute requirement.

It’s okay if your lizard eats more than the standard recommendation, so long as it doesn’t get too fat and its digestive system is working just fine.

This brings us to another important point – the fear of missing out. If your anoles don’t eat as much or as frequently as they should, they might begin to overeat to make up for it. This is a natural instinct, as the brain seeks to secure as many nutrients as possible, given that they’re rarer than they should be. Increase your anoles’ meal size and feeding frequency to circumvent this problem; they won’t fight as much during mealtime.

Some scuffles will remain, as this is normal behavior, but at least there won’t be anything serious.

Changes in Hormone Levels

Green anoles can experience hormonal changes for a variety of reasons. These include undergoing breeding season, experiencing health problems, experiencing stress, and, for males, sensing another male around.

These hormonal changes are nearly impossible to detect, but you can clearly see the aftermath.

Stress Due to Captivity

Green anoles don’t usually experience stress in captivity, so long as you provide them with optimal living conditions. These should include stable environmental parameters, a personalized tank layout, mimicking the lizard’s natural ecosystem, an optimized diet, and peace and quiet.

Even so, these reptiles can become stressed in captivity, especially during the first several days upon arriving in their new home.

The reptiles need time to adapt to their new habitat, during which they might be grumpier and more aggressive towards one another.

This is normal because they haven’t yet figured out their place in the ecosystem, which can take some time to work out. The best you can do at this point is monitor the situation and hope for the best.

Make sure that your anoles’ habitat is diverse, with a variety of climbing and hiding areas for when lizards prefer to avoid each other.

Feed them well and keep the environmental parameters at the ideal values, and the situation should stabilize soon.

Wrong Handling by Humans

One thing to know about green anoles is that they’re not fond of handling and petting. No reptile is, really, because reptiles aren’t exactly made for emotional bonding. But green anoles are extra sensitive and prefer to be left alone for the most part.

If you do need to handle them, make sure you always do it gently and watch the lizard’s behavior during that time.

If the anole seems uncomfortable or attempts to escape your hold, put it back in its habitat.

Frequent and improper handling can cause the lizard to become stressed, which will also influence its behavior towards its tankmates.

Lack of Hiding Places

This is a big one because if your anoles don’t have hiding places, they will constantly exhibit stress and aggression.

Reptiles, in general, are shy and reclusive, which is even truer for small lizards that lack any meaningful defensive abilities. So, they rely on their ecosystem to keep themselves safe from predators.

Sure, there are no predators to speak of in captive conditions, but the lizard doesn’t know that; instead, the reptile will function as nature programmed it to function.

So, it will still rely on its preferred safe spaces and hiding spots to cool off when stressed or calm down when rattled or irritated.

If the tank’s layout doesn’t provide the anole with these refuge areas, the animal may become stressed, aggressive, and fall sick with time.

Pain or Illness

This is a matter of special concern because green anoles cannot tell you if they’re in pain or what’s causing them discomfort. So, you need to figure that one out on your own by assessing the reptile’s behavior and appearance.

The lizard may exhibit various symptoms, depending on the nature of the disease, but some symptoms are pretty much universal.

Lethargy and irritability are two behavioral changes that are always present, no matter the condition your anole is dealing with.

If you notice your green anole becoming less active, showcasing loss of appetite, or turning more irritable and aggressive without a clear reason, consider it might experience a health problem.

If you can’t tell the underlying issue on your own, contact your vet for a more in-depth insight and professional assistance.

How do Green Anoles Fight?

Green anoles exhibit two combative behaviors:

  1. Warning and intimidation – The two lizards will first measure each other up, raise their heads, and attempt to intimidate one another. They often bob their heads from side to side and puff their chests to make themselves appear larger. The dewlap plays a critical role in this sense. This is a piece of red skin located under the chin that males can inflate to intimidate their opponents. The larger and redder the skin is, the more dominant the male. However, the dewlap-measuring contest doesn’t always pay off, in which case the lizards move on to the next phase.
  2. Physical assault – If everything else fails, green anoles will engage in combat to settle the matter once and for all. They will do so by interlocking their jaws and fighting that way until the winner is decided. The loser will flee the scene, but not before lowering and bobbing his head as submission.

Green anoles cannot inflict serious damage to one another, but they can experience cuts and minor injuries around the mouth.

These can infect in `a humid and warm environment, especially in a tank with improper hygiene. So, it’s important to limit the anoles’ aggression as much as possible.

Prevent Unnecessary Fighting Among Green Anoles

To prevent your anoles from fighting, consider the following:

  • Increase the tank size – We’ve detailed this aspect earlier, but a small reminder doesn’t hurt. Make sure all your anoles have sufficient space for them to be comfortable and peaceful with one another.
  • Adjust the anoles’ diet – Your anoles should eat as much as they want and as frequently as they need to. Stick with the standard of 3-5 insects every other day and go from there, depending on your anoles’ appetite.
  • Stick to the one-male-per-tank ratio – I advise against keeping 2 or more green anole males in the same tank. It doesn’t matter how much space they have. Green anole males will always fight with one another.
  • Monitor your anoles’ health – Sick anoles are always lethargic, irritable, and even violent. Make sure that your anoles remain healthy and monitor their condition regularly.
  • Keep environmental parameters stable – Keep the temperature, humidity, and lighting conditions within the ideal parameters for your anoles. Go for a temperature gradient between 75 and 90 F, a full-spectrum UVB lighting system for 10-12 hours of light per day, and a humidity level of 60-70%.
  • Make sure your anoles are compatible – Green anoles are not robots; they are unique individuals with different personalities and temperaments. Some anoles may be more aggressive than others, so you need to keep an eye out for that. If one anole is more violent towards its tankmates, despite your best efforts to mitigate that, removing the culprit from the group may be the best course of action.


Green anoles aren’t vicious fighters, but they’re not angels, either. They might occasionally fight, which is a perk of living in a group.

Mild scuffles are acceptable since they’re usually part of hierarchical plays designed to restore order and establish a social gradient.

But if the violence gets out of hand, you need to intervene to calm things down. Today’s article is of great use in this sense.

Robert from ReptileJam

Hey, I'm Robert, and I have a true passion for reptiles that began when I was just 10 years old. My parents bought me my first pet snake as a birthday present, which sparked my interest in learning more about them. read more...