SOTW: Venemous Dragons

Hello again everyone

I hope you have had an amazing week filled with productivity and hard work... No? Well you know that my blog is always here to alleviate some of the boredom and keep you on top on all your science need to know (by the way in case you didn't see they found a luminescent frog the other day!) Well I have a treat for you guys today! We have grown up with them in our fairytales and listened as parents told us that they never excited. I am of course talking about Dragons - and your parents lied! Meet the Komodo Dragon!

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Latin name:
Varanus Komodoensis
Conservation Status: Vulnerable

Komodo Dragons are the largest extant lizards alive. Male Dragons can reach a length of 10ft with females measuring a length of 7.5ft. These giants are only found on a small set of remote islands in South Indonesia. Komodo’s are classified as Vulnerable by the IUCN as there are only 4,000 individuals left in the wild, due to the increasing demand for Palm Oil.

It was recently discovered that dragon blood may provide a novel way of fighting against superbugs. Blood samples were taken from Komodos and analysed, there were 8 proteins of great interest that showed an ability to fight off drug-resistant strains common in hospital infections. Such amazing discoveries could lead to people hunting these Dragons to get access to their blood, further driving this species to extinction. However, I have faith in each and every one of my readers to realise that this would be irresponsible and stupid. Why? Because we have this beautiful thing known as technology. Proteins are more than able to be replicated under lab conditions without killing any more of these amazing lizards.

What does a female Komodo Dragon have in common with Virgin Mary?

Both are able to produce offspring in the absence of a male! In nature, we call this Parthenogenesis, a process that is rare in vertebrates. This was first discovered in two female Komodo Dragons: Flora from the Chester Zoo and Sungai at London Zoo (now deceased). Sungai to the surprise of her keepers produced four eggs despite her last male encounter being 2.5 years ago. This lead the zookeepers to two possible explanations, either Sungai had stored the sperm from that male or she had just shown the keepers that Komodos are able to do parthenogenesis. DNA samples were taken from each of the offspring, to find that they were exact clones of their mother. It was obvious, parthenogenesis was the only explanation. This was further validated by Flora who produced 8 eggs and had never come in contact with a male dragon.

This ability to switch between sexual and asexual reproduction appears to be beneficial, initially. This trait highlights a female's adaptability in situations where mate availability is limited.  There is, however, a dark side to this also. Parthenogenesis carries the same implications as inbreeding, where the offspring suffer from reduced fitness and increase the risk of extinction.

A Venomous Giant

One observation made back in the 1970’s by Walter Auffenburg led to the development of a myth that plagued the image of this carnivore in the eyes of the public. It was long believed that the Komodo Dragon, with pieces of rotting flesh left in his its mouth, harboured such a deadly cocktail of bacteria and viruses that one bite would lead to the death of its victim.  For years we have seen these dragons as bacteria laden villains that kill their prey in the dirtiest and most unhygienic way… literally. However, thanks to the work of Bryan Fry this myth has lifted, and it turns out the dragons actual hunting method is a work of evolutionary genius.

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Bryan Fry began debunking this myth by identifying the bacteria strains found in the Dragon's saliva. What he found confirmed his initial thoughts - there was a lot of bacteria, but no more than your average carnivore. Upon the realisation that there was no bacterial strain present that could cause the onset of symptoms observed when an animal is bitten, Fry began answering the question of how a Dragon actually kills.  

It turned out that Komodo Dragons were one of few lizards that went down an evolutionary path similar to advanced snakes - the development of an extremely sophisticated venom delivery system. Komodo Dragons are similar to other predators in that they take their prey by surprise and deliver a really nasty bite to the hind of the animal using their 60 razor sharp serrated teeth. At this point, the Komodo Dragon hangs back and waits for its venom to do its job.

Unlike a snake the Komodos venom glands are located at two points along their mandible, these lead onto a series of ducts in between each of their teeth. Using a bite-and-pull approach the venom oozes into the wounds of their prey while the dragon delivers a frenzied attack. Once delivered the dragon's venom gets to work. It begins by hindering the animals ability to clot their blood leading to continual blood loss, paralysis of the animals smooth muscle then sets in and finally, it causes a drop in the animal's blood pressure. The chemical present in the Dragon’s venom that is responsible for the drop in blood pressure was found to be as potent as that found in the world’s most dangerous venomous snake! The Taipan.

Well, that completes today's blog post on our planet’s very own Dragon that may not kill with its fire, but instead, uses a dual combination of venom and a serious bite! One last fact at top speed these Komodo Dragons can reach a speed of 12 miles per hour - that is pretty fast. My golden piece of advice if you happen to visit Komodo Island make sure you go with someone who is slower than you!!

Have an amazing weekend,
Science in the City xoxo

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