Are Komodo dragons venomous?

Komodo dragons are some of the most fascinating reptiles on Earth, but are these large dragons capable of delivering a venomous bite?

Found on only five volcanic islands in southeastern Indonesia, the Komodo dragon lives in a landscape that is rough and rugged, covered in grassland and forest.

Komodo dragons have a fearsome reputation. They are the largest living species of lizard on Earth, which is typical of many creatures found living on islands. Because they are so large, they are top of the food chain where they live, dominating the ecosystem and taking advantage of all the food on offer and over time they have evolved into highly efficient predators. They mainly hunt through stealthily ambushing prey, sneaking up on other animals and catching them unawares.

We know Komodo dragon’s saliva is full of deadly bacteria, but is there venom lurking in there also?


Is it venom or bacteria in their saliva?

Relatively recently it has been claimed that Komodo dragons have a deadly venomous bite. One that is capable of killing prey and poisoning their bloodstream. But whether the reptile is truly venomous is a fact scientists are still figuring out.

Recent studies have shown that Komodo dragons, indeed all monitor lizards, have saliva that is venomous to some degree.  However, this ‘venom’ is not like that of, say a cobra, that can kill prey in as little as a few hours. So the large dragons have a few tricks up their sleeves.  It appears that the venomous saliva combines with infectious bacteria, blood loss, as well as physical injury, to kill prey.

It is thought the dragons have two glands in their lower jaw, which administers several toxic proteins. Alongside this they are able to deliver an anticoagulant to their prey, meaning their blood is unable to thicken and clot. Not great if you’ve just been bitten and need to heal. The bacteria found in their saliva are a mixture of the well-known E.coli and Staphylococcus strains among many others. Some studies have shown there could be as many as 53 different strains of bacteria lurking in the mouths of these wild reptiles. It is highly likely that prey bitten by a Komodo dragon will suffer from sepsis and infection very soon after the bite due to the extremely harmful and hostile bacteria that are able to spread and replicate quickly.

Despite this, they like to keep their mouths clean. The bacteria isn’t a result of rotting flesh left lingering in the mouth for days, as they like to spend time licking their lips and chewing leaves to ‘clean their teeth’ after a meal.

However it has been noted that Komodo dragons in captivity will lose the bacteria from their saliva because of their clean environment and the use of antibiotics. There have also been cases of zoo keepers being bitten by Komodo dragons and living to tell the tale!

Komodo dragons have been known to hunt in groups as well as on their own.


The argument for venom came much later when in 2005 a team of researchers at the University of Melbourne spotted localised swelling, bruising, and redness at the site of a dragon bite. This lead them to think there may be more than just bacteria hiding in their saliva. Alongside the anticoagulant found, there are a number of toxins, which can lead to low blood pressure, muscle paralysis, and hypothermia. However these symptoms could also be caused by shock, blood loss, or the bacteria and so whether the Komodo dragon is venomous or not, is up for dispute.

Wild Komodo dragons rarely attack humans. We do not make up part of their diet so it’s unnatural for them to try. That doesn’t mean it hasn’t happened though, and there are numerous reported cases of Komodo attacks, from stranded tourists, to young children.

So how does this help them?

Killing prey in this way is a very clever tactic for the dragon, particulary as its large size makes it somewhat cumbersome. They are able to run relatively quickly, with a top speed of 11mph (18kph), but they can only sustain this for short amounts of time. So as long as they can get close enough to have a bite – they are able to sit back and wait for their meal. It usually takes about 24 hours for a creature to succumb to a dragon’s bite and once they have, the reptile has an amazing sense of smell to guide them to their dinner.

In short, few animals are likely to survive a dragon attack and that includes humans. Whether it’s bacteria, blood loss, or indeed venom, death can often be slow and pretty painful. So the secret is, stay away from wild dragons and do NOT get bitten!



Don’t want to miss out? Become a digital reader today, order back issues, or subscribe for a great deal. Find us on Facebook here: search and on Twitter here: search to keep in touch and up to date

Photograph credit: Molly GoossensBrice Li