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Suddenly Aggressive Bearded Dragon [5 ways to manage]

Suddenly Aggressive Bearded Dragon [5 ways to manage]

Bearded dragons are renown for being docile and friendly to their keepers. However, occasionally there are some pet owners that may find a suddenly aggressive bearded dragon straight after winter, as spring arrives. Seasonal aggression is likely to be a male, related to sexual maturity and the arrival of mating season. This seemingly angry outburst expected to be a short seasonal change.

Breeding male bearded dragons are not normally aggressive or angry towards their owner and if they are, it is more likely to be bluff (Brown, 2012).

Sometimes the unusual behaviour may start just before a year old and other times it might not be seen until the bearded dragon hits 4 years old. Aggressive hormonal behaviour is linked to males however, females can also become a little aggressive to a lesser degree.

Seemingly suddenly aggressive bearded dragon related to breeding will often start when it comes out of brumation, or at the beginning of spring. At this time, bearded dragons are ready for mating and hormone levels are up. The aggressive behaviours may last for a couple of weeks or longer.

Scent may have a significant part to play in aggressive bearded dragon responses. It was once thought that agamid lizards were mostly dependent on visual cues for their social interaction, however others have found that pheromones also have an important role to play (Gans and Crews, 1992).

The role of scent on the aggressive behaviour of the male Iberian wall lizards was studied by Lopez and Martin (cited Norris and Lopez, 2011). The scent of some males familiar with each other were masked with the scent of an unfamiliar male. This resulted in aggressive responses reserved for unknown males. When a male was introduced to another male masked with its own scent or even that of another familiar male, the aggressive responses were less aggressive.

9 behaviours that may be apparent in a male bearded dragon that has become suddenly aggressive with season may include:

  1. Blackening his beard and body.
  2. Bearded flared.
  3. Puffing up his body, tilting it slightly sideways to look bigger.
  4. Lashing tail.
  5. Mouth open, may include hissing.
  6. Running around and head bobbing.
  7. Clawing to get out of the tank, glass surfing.
  8. Suddenly lunging at a hand in the tank without warning.
  9. Attacking tank furniture or anything that comes near him.

Handling an Aggressive Bearded Dragon

If a bearded dragon becomes aggressive, no matter what the reason, it can cause considerable damage to fingers, or any soft flesh. It can quickly wrap its tail and legs around a hand and bite down.
It is best not to handle the bearded dragon until it calms down. In the case of seasonal aggression, the angry outburst could take a few weeks to return to normal. If the bearded dragon must be handled at such a time, use a towel or some other buffer between yourself and the lizard.

Where attempts to attack are made, record details of the event. For example:

  • What was going on around him at the time?
  • What color of clothing was being worn. Was there any black, red or other color?
  • Was anyone wearing nail polish? If so, what color?
  • What sort of scents may have been present? Any scents that a human nose could detect?
  • Who was around?
  • Was he indoors or outdoors?
  • Was it in the enclosure, usual territory?
  • Were there any other pets?
  • Was there a reflective surface the bearded dragon could see himself in?

Note that in iguana’s, women’s menstrual cycle has been considered a factor for sudden aggression.

What signs of aggression did the bearded dragon display? For example:

  • Black beard perhaps extending on the back and tail.
  • Hissing.
  • Puffing up the body and tilting to one side to look bigger.
  • Bobbing his head.
  • Lunging at a hand.

Study the notes you take over time and look for patterns which can be used to prevent future events.

A suddenly aggressive bearded dragon is one of the main reasons that they should not be kept in small tanks with others. Passive behaviours as a bearded dragon grows does not prevent a sudden change of behaviours as hormones and other seasons changes take place.

In iguanas, sudden seasonal aggression is common. Male iguanas can see a male human as a threat to territory and may also try to defend access to human females in the household (Lock, 2018).
Suddenly Aggressive Bearded Dragon Outside of Breeding Season

Considerations for a suddenly aggressive bearded dragon not related to seasonal changes could be:

  1. Chronic stress (Benn et al, 2019)
  2. Pain
  3. Defence
  4. Accident, especially if the scent of another male bearded dragon is on the hands of the keeper.

Klaphake (UD) documented that in iguana’s impacted femoral pores could potentially be linked to sudden aggression. The evidence may be simply coincidental however, worth considering since impacted pores can cause considerable pain. Klaphake (UD) found that once the femoral pores were relieved the iguana’s behaviours returned to normal. Interestingly, the femoral pores secrete a waxy substance that gives away the most personal secrets. More on that in the post secrets of femoral pores.

5 Ways to Manage Seasonal Aggressive Bearded Dragon Behaviour

  1. Chances are you will not be able to calm the bearded dragon down, but you may be able to transfer the energy. Provide a stuffed toy or a small microwavable bean bag warmer. The bean bag warmer is ideal as it can be slightly warmed prior to giving to the bearded dragons. Ensure that anything provided will not present danger from being able to tear bits off or become a fire hazard. The toy may be attacked, mated or perhaps both.
  2. Cover reflective surfaces that may reflect the bearded dragon’s own image back to him. This could be seen as a rival.
  3. If there are other lizards in the same room, separate their habitats further.
  4. Temporarily reduce the lighting period to trick the bearded dragon into thinking it is not the right season for breeding.
  5. Avoid handling and allow the time to pass.

For information on the effects of desexing (neutering) on aggressive bearded dragon behavior see the post on spaying and neutering.

Suddenly Aggressive Bearded Dragon Conclusion

Although typically docile, a suddenly aggressive bearded dragon at the beginning of spring is likely due to seasonal changes cueing breeding time. This may not be the cause in all cases and each should be assessed on its own merits.

Consider the cues and stimulation the bearded dragon may be getting from the environment around him. Punishing aggression would be unjust and unproductive. If seasonal aggression is suspected, try the techniques above to prevent or deflect the bearded dragon’s aggression or energy.

Monitor and document the immediate environment and factors which appear to lead to aggression. Review the trends that are uncovered in the documented history to identify ways to prevent aggression in the future. Discuss with your vet.

If your pet is not aggressive, perhaps just scared, try taming a bearded dragon.

Has your bearded dragon become suddenly aggressive? Tell us your story in the comments.


  1. Benn, A. L., McLelland, D. J. and Whittaker, A. L. (2019) A Review of Welfare Assessment Methods in Reptiles, and Preliminary Application of the Welfare Quality® Protocol to the Pygmy Blue-Tongue Skink, Tiliqua adelaidensis, Using Animal-Based Measures. Animals (Basel). 9(1): 27.
  2. Brown, D. BVSc, BSc (2012) A Guide to Australian Dragons in Captivity. Reptile Publications. QLD Australia
  3. Gans, C., and Crews, D. (1992) Hormones, Brain, and Behavior. Bibliovault OAI Repository, the University of Chicago Press
  4. Klaphake, E. DVM, DACZM, DABVP (Avian Practice), DABVP (Reptile & Amphibian Practice) (UD) Femoral Gland Biology and Possible Medical Concerns in the Green Iguana, Iguana iguana.
  5. Lock, B. A. (2006) Chapter 13 – Behavioral and Morphologic Adaptations. Ed: Mader, D. R. Reptile Medicine and Surgery 2nd Ed. W.B. Saunders. Pages 163-179
  6. Lock, B. (2018) Aggression in Captive Reptiles. Veterinary Partner
  7. Norris, D. O., & Lopez, K. H. (2011) Hormones and Reproduction of Vertebrates Vol. 3. Reptiles. San Diego, CA: Elsevier Academic Press Inc

Has your bearded dragon come out of brumation a little crazier than it went in? With the arrival for spring for some,…

Posted by Bearded Dragons World on Saturday, 16 May 2020

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Thursday 29th of April 2021

I adopted my 5-year-old full-grown beardie about 3 months ago and he was timid at first but after a couple of weeks, he went with me everywhere then but overnight he became a totally different pet. He started going flinching at every movement and almost twitched at everything he saw move. He started running around his enclosure trying to climb out and showed signs of aggression such as; puffed up, black beard, and mouth gaping and hissing. I'm thinking it's because spring is coming but I'm worried I did something wrong. He used to be so loving and would cuddle but somehow I feel as if something triggered him to become so aggressive and defensive.


Friday 30th of April 2021

It is quite possible it is something to do with the environment. Might not be in his enclosure but something he sees. As much as it could be aggression, they are all signs of fear. Has the temperature got warmer lately? If so, possible that he was cooler before muting his reaction to anything going on and now it is warmer he is able to demonstrate his situation more clearly.

Catherine Prillo

Sunday 29th of November 2020

Billy-The-Beared has never been particularly cuddly; but he’s never been this bad! He has a huge tank, with a warm and a cool side, natural branches, two ponds, edible live plants, UVB light, basking light, hiding places and so on. He gets fresh chopped veggies twice a day and about twenty or so mealworms and calci-worms also twice a day. He has grown like a weed and seemed very happy. What am I doing wrong??? He hisses and bites me and no longer likes being handled. Is it brumation? What do I do?


Tuesday 22nd of December 2020

So much more to know to be able to provide a useful answer to you. I would suggest hormones may be kicking in and/or he is scared. Fast growth is related to diet. Size determines age more than calendar. This means that a 6 month old bearded dragon can have hormones going mad if it is large enough. Brumation is more likely to create a sleepy, lethargic bearded dragon than angry. Try putting a piece of cloth in the area with your scent over the next week or so and working your way from there, being extra patient. Best of wishes.

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