The Komodo Dragon is a truly wondrous beast. According to venom expert A/Prof Bryan Fry it has a kill rate for its normal prey higher than lions or great white sharks. (Remember that if you have to choose which to be attacked by). As if its fearsome teeth and capacity to break animals against large objects with the power of its neck muscles are not enough Fry proved in 2009 that the dragon is actually venomous.
The venom causes the few animals that survive to bleed out quickly since it contains a powerful anti-coagulant as well as proteins that lower blood pressure. Fry has uncovered a lot of new venoms in various species and hopes some of them will prove to have medicinal benefits – the demand for drugs that lower blood pressure being rather large. Although reducing blood pressure is a common technique for venomous animals, Fry says the dragon is particularly promising because its prey are larger animals – “more closely related to us than rodents or marsupials”. The dragon originally evolved eating smaller examples of Australia’s megafauna, but has had plenty of time to adapt its venom to a new diet of pigs and deer.
Which is all very interesting, but Fry has now added a new twist to his dragon research. One of the best known things about the dragon is that it also has a weapon unique amongst all known predators. Its mouth is full of bacteria that induce septicaemia. Prey large enough to escape the dragon’s teeth, vicious jerking and venom eventually die from their wounds turning septic, making an easy, if unappetising, meal. This mainly means water buffalo, but naturally plenty of local people worry it may one day include them.
This story must be true – it’s in every documentary on the dragon, including David Attenborough’s, and it gets a run in Douglas Adams’ marvellous book Last Chance To See. Adams also goes to great length on how bad the dragon’s breath is as a result of this bacteria.
Except the story is rubbish.
The dragon’s mouth contains less bacteria than most predators, as it rubs it against leaves after feeding. The reasons the buffalo die of septicaemia is that their natural instincts when attacked is to go and stand in water. In their native habitat this means large areas of fresh water marshes. On the islands where they interact with dragons, since being introduced three centuries ago, it means tiny waterholes filled with sewage from all the other water buffalo that like to spend their time in the limited stocks of water around. I think you can see where this is going. “It is when the water buffalo go stand in the toxic water with gaping wounds that they get infected,” says Fry. “They are basically going to the bathroom directly onto their wounds.” Adams presumably didn’t get close enough to a dragon’s mouth to test the story on their breath, but as you can see above, Fry has, and says “it smells no worse than my staffies at home.”
If you think about it, Fry’s idea makes much more sense than the old one. The dragon has only encountered the buffalo for a few centuries, and has not had time to evolve a new weapon. Certainly it once took on very different prey, but is it really likely the bacteria would have lasted through millennia of uselessness when there was nothing on the islands so large the dragons couldn’t take it down with what they have? It also seems an unusually charitable act for a reptile to kill prey in such a way that it takes weeks to die, ensuring that some other member of the same species will get to benefit, since the odds of the original biter being around when death occurs are slim.
I think this is pretty interesting in itself, but am fascinated by the reaction Fry tried to back up his theory. “We had zookeepers refusing to let us study their animals,” says Fry. As if that wasn’t enough. “Some of them were calling other zoos telling them to not take part,” says Fry. “I felt like a climate scientist.”
When Fry eventually got access to enough dragons to test the theory he got his paper through peer review at the Journal of Zoo and Wildlife Medicine, yet the idea was so controversial they sat on the paper for a year before publication.
I pointed out to Fry that climate scientists are obstructed because their research conflicts the interests of some of the largest businesses on the planet. Despite my ironic last post, zoos are not exactly emblematic of financial power. Fry agreed, “there is no monetary effect here at all” – komodos won’t stop attracting visitors just because they kill their prey in a different way from previously thought.
I can see climate change denialists, stung by Fry linking himself to their victims, jumping on this as evidence of how protective scientists can be of their turf, and how bad ideas can survive through groupthink. Unfortunately for them, the theory breaks down in several ways. Firstly, as Fry notes, “Most zookeepers are not scientists.” This is not to knock them. I’m a big fan of what Rachel Lowry is doing at Zoos Victoria, but zookeepers are generally chosen for skills different from the research enthusiasm that is the primary characteristic of scientists. Moreover, the fact that Fry eventually got his work published does rather discredit the idea that peer review kills radical ideas.
However, I think this example does tell us a bit about the circumstances where science can be wrong. Since the publication of John Cook’s research on peer reviewed papers relating to climate change we’ve seen quite a few references to 97% of scientists agreeing that humans are causing global warming. While deniers would prefer to ignore the fact that 97% of climate scientists are onside with the IPCC, when they can’t dodge the fact they point out that science is not a democratic vote. Einstein’s swipe at the 50 Nazi scientists who disputed his “Jewish physics” that “a single fact would be enough” gets quoted a bit.
It is indeed true that sometimes 97%, or even 99% of scientists in a field turn out to be utterly wrong. Most of those propagating the komodo mouth bacteria theory were not scientists, but certainly there were a few on board, possibly including 100% of people who had investigated the dragon until Fry turned up. Which is why what matters is not so much the number of scientists, but the number of papers.
Fry notes that the Komodo theory was built on just two papers, both by the same team “none of whom were microbiologists”.
I see this sort of thing quite often. A widely believed theory gets overturned throwing a whole field of science into a new light. But what we see, over and over again, is that when this occurs the old order was built on just a handful of papers. Usually no representative of some key area of science was included in the teams that built the myth.
The contrast with climate change could not be sharper. Cook looked at almost 12,000 papers, and could have included more if he had expanded the time period he studied. This is probably the one scientific question where the old cliché that the participants stretch “from astronomers to zoologists” is actually true. Despite the denialist cries that geologists have been locked out of climate change research, there would be hundreds of authors amongst those 12,000 papers with geology backgrounds.
Any scientific theory could turn out to be wrong, but some are much, much more likely to go that way than others. And Anthropogenic Global Warming has to be one of the least likely. Septicaemia inducing oral bacteria in the world’s largest lizard, on the other hand, was always a prime case.
Update: The University of Queensland sent me some extra photographs of Fry and the dragons. This one so brilliantly captures Fry’s personality I had to add it here.