Monday, December 15, 2008

There are no longer 23 species of crocodilians

In fact, there are 25 of them. Possibly more. While we are all extremely concerned about the handful of critically endangered species that are in serious danger of disappearing from the wild forever, it would seem that there are a few crocodilian species that we know nothing about. It's understandable. For a start, most crocodilians look very similar to each other. You have to be very familiar with each species before you can reliably tell them apart, and even then it can leave experts guessing without a very detailed examination of the skin. To complicate matters further, some variation in appearance is normal - a scale here, and colour change there. There are many, many sugggested species, sub-species and regional variations of crocodilians, but up until recently there were only 23 commonly-accepted species.

Enter genetic analysis. This is a tool that boils all those visible and invisible differences between species into a sequence of base pairs - a genetic formula for a species. So if you compare two individuals you'll always find differences (unless they are identical clones). The problem is, which of those differences are important in determining whether they are genetically compatible? In other words, whether they are the same species or different species?

To complicate matters even further, hybridisation is possible between quite a lot of crocodilian species. You remember the part during biology lessons where the teacher told you that only if two individuals could breed and produce fertile offspring they were of the same species? Well, it was wrong. Crocodilians demonstrate this very well, and it makes it even more difficult to say for certain which species is which.

So, genetic analysis should be able to solve this dilemma... if we knew what to look for each time. The main problem with some of these crocodilians is getting enough genetic samples covering their entire distribution to enable meaningful comparison. Without it, you end up with uncertainty, but with sufficient samples you can say with more confidence whether the species you're testing comprises one or more species. This is essentially what Mitchell Eaton and his team from the American Museum of Natural History have done with the African Dwarf Crocodile (Osteolaemus tetraspis). It was always suspected that there were two subspecies of dwarf crocodile: O. tetraspis tetrapsis and O. tetraspis osbornii based purely on morphological differences. Comparing photographs of the two candidates, the differences in the shape of the skull and the scalation were quite noticeable, but this alone was never sufficient evidence to separate them. But now that Eaton's team has compared the genetics across a sufficient wide range it's clear that there are major genetic differences there. The only thing is, there are enough differences to indicate three separate species, not just the two that were previously suspected. Perhaps the presence of this third species was sufficient to confuse any meaningful morphological comparisons earlier? Whatever the reason, we'll all have to revise our websites and our textbooks!

The three species? The third is as yet unnamed, but the first two are O. tetraspis and O. osbornii. It will be interesting to see what they name the third. Suggestions welcome!

Thursday, December 04, 2008

The largest saltwater crocodile in the world

[Updated July 2012]
When this story was written back in 2008, Cassius was indeed the largest saltwater crocodile in the world that we knew of. But in November 2011 we measured a much larger one called Lolong, and in June 2012 he was officially declared by Guinness to be the largest crocodile in captivity. The full story is in my 23 June 2012 blog post which is here.

[Original post]
How many times I have been asked this question: which is the largest crocodile in the world? Of course I always say that it's a saltwater crocodile (Crocodylus porosus) because the evidence we have supports that. But there's not always a lot of actual evidence of large crocodile sizes, just plenty of "big croc" stories. Still, the biggest crocodile ever measured (with a tape measure) was around 6.3 metres long (20.7 feet) from Papua New Guinea.

But what about the largest living crocodile? There may be several huge crocs living in the wild that we don't know about, but the largest living crocodile in captivity has been living on Green Island near Cairns for over 20 years. His caretaker is George Craig, a former crocodile hunter who now runs Marineland Melanesia, a shrine dedicated to crocodiles on the island. It is quite a remarkable place, which is entirely reflective of how remarkable George himself is. You see, George loves crocodiles with the kind of passion that you rarely encounter. He respects them enormously. This is why we were very keen to meet and talk with him on a recent trip to Cairns. The truth is we could have talked for weeks about crocodiles, but we only had a few hours. George was very keen to show us his pride and joy, the largest living saltwater crocodile in captivity. His name is Cassius, and he originally came from the Northern Territory. At the time he was a little under 18 feet (5.5 metres) long, but he's now around 18.5 feet (5.6 metres). Like many extremely large crocodiles, Cassius is as gentle as a lamb around his keeper, unless some food is dangled in front of him. Then, looking remarkably like a dinosaur from a forgotten age, he explodes into action and grabs the food from George. The word "grab" doesn't really do it justice, as the item of food often explodes under the pressure of those jaws. It's a remarkable and sobering sight, and if you ever need reminding how awesome crocodiles really are then a trip to Green Island to see Cassius is essential. Don't forget to talk to George Craig - rarely will you find anyone who knows more about crocodiles and understands them like he does.

Sunday, November 16, 2008

Snowy and the Cage of Death

There's been a lot of publicity lately about the new crocodile exhibit that's opened in the middle of Darwin city centre called Crocosaurus Cove, and nearly all of it has concentrated on the curiously named "Cage of Death". Despite sounding like a good way of getting rid of excess tourists, the cage (which is actually an octagonal cylinder made from thick acrylic) is a way of getting people into the water - safely - with the crocodiles on display.

Response to this has been mixed, some believing that it's a great experience and a new way of seeing crocodiles, others thinking that it's a crazy thing to do, and yet others who believe that it's terrible and cruel to the crocodiles. Of course, people get out of it what they want, but frankly we're more inclined to think it's a good thing.

Of course, complete transparency here: although we're an independent company, we did put the educational materials together for the exhibit, and were involved in moving the crocodiles in from the local crocodile farm. But I must admit I was skeptical about the Cage of Death at first. Still I have to be honest: just being in the water with a large crocodile is quite a thrilling experience. Part of your mind tells you you're safe, the other part is trying to convince your body (unsuccessfully) to run away, run away. It must be a basic human response when faced with a large predator, especially when you're in its element and not your own.

How do the crocodiles respond to all this? What they don't do, of course, is view the Cage of Death as a feeding opportunity. At first they were somewhat annoyed by it, but they quickly learned that it was neither a threat nor a problem, and often do not deign to give it any further attention. But if you're in the water when they're in a curious mood, they'll come over and check it out. Crocodiles do get a rep as being bloodythirsty killers, but in reality they're just looking for opportunities in a completely detached, crocodile-like way. There shouldn't be any stress involved, particularly for a captive crocodile that is happy in the knowledge he's got plenty of food and space available. That's all crocodiles in the wild are looking for most of the time, after all.

And the enclosures at Crocosaurus Cove are certainly in keeping with the modern zoo mentality of giving the animal what it wants first, and what humans want second. The great power of zoos, of course, is to educate people. Crocodiles are animals that people need to know about, especially if they live in crocodile habitat or visit crocodile habitat. It should be our responsibility, and that of local governments, to ensure that people understand safety around crocodiles. Failure to do this is splashed over the front page of every newspaper in the country, and crocodiles sink yet further in public perception. As long as those zoos are not failing in their duty to provide their animal occupants with all the essentials to keep them happy (not just to keep them alive) then they can play a valuable role.

Monday, November 03, 2008

Award-winning crocodiles

It's always great when crocodiles win awards. When a natural history programme featuring crocodiles wins an award, you know the toothy ones had a fairly significant role to play in it. Especially when the programme in question is Life in Cold Blood: Armoured Giants which just won the Golden Panda at the recent Wildscreen awards held in Bristol, UK. I like to think that our saltwater crocodiles had a part to play in winning, of course, as they featured in perhaps the most spectacular sequence in the programme - cooperative feeding on fish, which was filmed here in northern Australia. Being the scientific advisor for the crocodile half of the programme, I was able to persuade the BBC to bring Sir David Attenborough out to work with us on this crocodile sequence, because I knew exactly how spectacular it would be to get David and the crocs in shot. Working with David for a whole week was an experience we will never forget. This is someone who was responsible for getting me into a life of wildlife in the first place, and I felt this was a way of paying him back in some tiny way.

Monday, October 20, 2008

Travels around Queensland

It's been a little while since I last posted a blog update, but that's because Erin and I have been travelling around Queensland working on some crocodile consultancies. We've been staying in isolated communities usually with very limited communications, and often working at night at very odd hours - going to bed at 6pm and getting up at 1am to catch the right tide never seems to be easy. Yet there's something oddly liberating about working for several hours on a river at night and then getting back just as the sky begins to brighten in the east and the first rays of dawn appear.

We get back to Darwin in late October, so hopefully normal blog service will resume then. That is, after we've both caught up on our sleep.

Tuesday, September 02, 2008

Creatures of Bullo River

The land around Bullo River Station is spectacular, to say the least. And its inhabitants are equally remarkable. As part of our ongoing study into pygmy freshwater crocodiles (see previous post) we keep bumping into critters that seem even more intriguing.

Every two to three days, Franz Ranacher drops us off with his Robinson R44 helicopter into the upstream escarpment country. Once the fading sound of rotor blades has left us behind, we're surrounding by the sounds of birds, chirruping insects and squeaking frogs. You really don't have to go very far to find something fascinating. Our surveys involve long walks during the day along the creeklines and isolated pools, returning at night to spotlight for crocodiles and hopefully catch a handful for tissue samples. So we get to see a lot of diurnal and nocturnal wildlife. Occasionally we find something that really takes our breath away. Apart from the crocodiles of course, which are always cause for excitement.

So if you'll excuse my slight devitation from the crocodile theme of this blog, here are a couple of really cool critters. You can call them honourary crocodiles if it makes you feel any better about it!

The first is a Northern Knob-tailed Gecko (Nephrurus sheai). This little fellow was hot-footing it along beside our mozzie dome one night, looking more like a wind-up mechanical toy than a reptile. We managed to intercept him with the camera and took a few snaps. They really do have a tiny little, stunted-looking knobbly tail. I'm sure the first one to be found was suspected of having its tail bitten off when it was young... and then the second... and then they all seem to have these bizarre tails! They also have an enormous head, so much that they always seem to be in danger of pitching nose-first into the sand. Their entire body is also covered with tiny, rosetted scales. With their huge eyes and disarmingly amused expression, they're not the kind of thing you forget easily.

The second is a Leichardt's Grasshopper (Petasida ephippigera), which seem like they've come straight out of a children's toyshop. Some Aboriginal people call these "Children of the Lightning Man" and you can probably see why. As you can probably imagine, they taste pretty bad, which explains why they're pretty laid back when you find one. Not that we had any intentions of eating one to test the theory. These grasshoppers are also used as a sign of the oncoming wet season. Although it is still early September here, the humidity is starting to rise and the days and nights are getting progressively warmer. These kinds of triggers cause the adult form of the grasshoppers to emerge, where they are said to look for the lightning storms that signal the beginning of the wet season in November.

Monday, September 01, 2008

Pygmy crocodiles of Bullo River

Back in early 2006, we were contacted by Marlee Ranacher from Bullo River Station about their freshwater crocodiles. Not any old freshwater crocodiles, however, these were pygmy freshwater crocodiles. These tiny bundles of attitude are essentially very similar to freshwater crocodiles (Crocodylus johnstoni) but they live in far upstream escarpment areas around the Northern Territory in particular. In these areas there is very little food, mostly various species of small fish no more than a couple of inches in length, small crustaceans and... well, that's about it. As a result of not having much food available, they don't grow very large. They are essentially stunted crocodiles, but they have adapted to this unique environment. And, more importantly, they are essentially geographically isolated from downstream, "normal" freshwater crocodile populations. That in itself makes them interesting, but they have the potential to be even more interesting.

If they are geographically isolated and there is little or no genetic input from more downstream populations, then they have the potential to become genetically distinct over many generations. It's evolution at work. One tantalising clue comes from a breeding pair of these tiny crocodiles, originally from the upstream Liverpool River, that were bred by Melbourne Zoo. The offspring were fed a normal captive diet, and therefore they should have grown into normal freshwater crocodiles. However, they did not - they were also stunted. Although that doesn't prove anything, it makes enquiring minds want to know whether they are indeed different.

There is another spanner in the works. Cane toads! These warty horrors can get into the most amazing places, and that includes upstream freshwater escarpments. We already know that freshwater crocodiles eat cane toads, and that they are susceptible to their toxin, and a recent study showed a 70% decline in crocodile populations before and after cane toad arrival. Pygmy crocodiles, being smaller, are more susceptible to the toxins from these toads, and therefore we are all extremely concerned about the long-term impact of toads on these pygmy populations.

So we are here at Bullo River conducting surveys and to collect tissue samples from a representative sample of crocodiles. The surveys involve walking along an upstream creek during the day, mainly to find pools and to figure out how to climb between them - some areas are quite treacherous to get around - and then walking back at night with a headtorch and spotlight to count the number of eyeshines in each pool. Crocodiles have a reflective layer in the retina of their eyes, and the reflected light is bright red so they are quite easy to see at night if they are on the surface. The problem is, many crocodiles are not on the surface - usually they're hiding amongst vegetation, under logs, and particularly in cracks between submerged rocks. So you really have to spend a lot of time looking around, double and triple checking each pool.

Catching them to take a tissue sample is another challenge. The best, and perhaps only effective way of doing it is to get into the water and catch them by hand. Most of the time this isn't a problem because they're fairly small, although trying to hand-catch a 1.5 metre crocodile (the biggest any pygmy croc appears to get) requires a bit of care! Many of the crocodiles are also very naive towards people and will happily swim over to check you out. Some of the larger, territorial males aren't best pleased by your presence either. Once captured, however, they become quite placid and can be measured and photographed with ease. We take a small sample of tissue from the tail, basically a piece of mostly dried skin, and then release the crocodile back into its pool where it glowers at us. If only we could tell them that it's all in their best interests.

We're here for a few more days yet and we've seen some pretty amazing creatures up here, so there'll be more to come.

Thursday, August 21, 2008

2nd Annual Crocs Galore Gala

Lori Watkins of the Crocodilian Advisory Group has just sent me the following press release about the 2nd Annual Crocs Galore Gala. Make sure you contact Lori (see below) if you want more information about what sounds like a lot of fun.

North Carolina Museum of Natural Sciences in Raleigh, NC

Please come join us for the 2nd Annual Crocs Galore Gala on Saturday, October 25, 2008 for a night of fun to support crocodilian conservation, education and research of the most critically endangered species!

Croctober Halloween Event: FREE to all visitors...9am-5pm: Event will include:

  • coloring/craft croc tables for kids.
  • crocodilian artifact/biofact table.
  • CAG merchandise table.
  • Face painting table.
  • Opportunity to have your picture taken with a 'ghostly' albino alligator
  • Live crocs.
  • Live animal show featuring reptiles from around the world by Ken Alfieri from Alligator Adventure.
  • Slide presentation about Crocodile Conservation by member of the Crocodilian Advisory Group.
  • Raffle of a gharial skull

Evening event 6 pm to 9 pm: 2nd Annual Crocs Galore Gala hosted by the Crocodilian Advisory Group with guest speaker Dr. Brady Barr from National Geographic... the only biologist to capture all 23 species of crocodilians in the wild! Evening Event is by ticket purchase $25 for adults, $15 children 4-13, under 3 free: questions or purchase of tickets...

email Lori Watkins, CAG Fundraising Chair at

Gala includes heavy hors d'ouvres, beverages, including wine & beer.

  • coloring/craft croc tables for kids.
  • crocodilian artifact/biofact table.
  • CAG merchandise table.
  • Live crocs
  • Scavenger hunt
  • Live/Silent auction, with all proceeds going 100% to the Crocodilian
  • Advisory Group.

Room reservations at the: CLARION HOTEL STATE CAPITAL, 320 HILLSBOROUGH ST, RALEIGH, NC 27603-1786 USA, Phone: 919-832-0501. If anyone wants to come to the event and reserve a room, rooms are $79/night and they are blocked off under the Crocodilian Advisory Group.

Closest airport is Raleigh/Durham.

If you are unable to attend the event, but would still like to help, please make checks out to the Toledo Zoo, Croc TAG in the memo line and send to: North Carolina Aquarium on Roanoke Island, Attn: Lori Watkins, PO Box 967, Manteo, NC 27954. If you would like to donate items for the live/silent auction, please contact Lori Watkins at Check out the Crocodilian Advisory Group website at Thanks!

Lori Watkins, Crocodilian Advisory Group Fundraising Chair Aquarist/Herpetologist North Carolina Aquarium on Roanoke Island

Monday, August 11, 2008


No really, I spelled that correctly. You see, we have a crocodile called Smaug in our garden. He's a 14.5 foot (4.5 metre) long Australian Saltwater Crocodile. We called him that because, well, he looks like a smug dragon that could be sitting on a large mound of golden coins. For those that don't immediately see the references, that's what Bilbo Baggins finds the dragon Smaug doing near the end of J.R.R. Tolkien's The Hobbit. Considering that Peter Jackson and Benicio del Toro are producing the movie version of the book at the moment, we thought of sending them Smaug's audition tape. He's quite a dynamic presence, as you can see from the photograph (thanks to Graeme Sawyer).

Oh and incidentally, the board that we used to carry Smaug on when we built the enclosure? That's the Smaugasboard.

Thursday, July 31, 2008

Science Writer Awards 2008

As a scientist I've always strongly believed in the necessity to communicate science to the world at large. Science is often very much misunderstood, and poorly communicated. To many people the words "science" or "scientist" conjour up images of a bespectacled nerd in a white lab coat mixing the coloured contents of test tubes. In reality science affects us all and is of critical importance to our survival in the future... and the survival of species and habitats on this planet, which of course is one aspect of science that concerns me.

So the ability to communicate science and what makes it important is a real asset to a scientist. The recent Science Writer Awards 2008 present a number of excellent essays written by young scientists that highlight just how exciting and passionate science can be. They are all worth a read, as is watching the short video by luminaries in the field of science communication.

In some ways it is a little easier communicating how exciting science can be when you work on crocodiles, so I always admire those who can communicate a little of the passion they feel about their own area of science.

Monday, July 21, 2008

Crocodile defence

It's rather chilly in Alice Springs at this time of year. I know that because I'm here right now, in an airport waiting lounge where staff keep flinging the outside doors wide open, letting in an icy blast of air that just isn't fit to be allowed inside any building. I'm waiting for my connecting flight to Sydney, where I hear it's so cold that penguins have taken up residence on the harbour bridge. I'm not sure if that's accurate, I'm sure I read it somewhere.

I hate waiting in airport lounges, especially when you look up and realise that the board informing you of your flight departure time is suddenly replaced with the time of a completely different flight. Oh no, have I missed it? Did they change it? Can I be bothered to get up from my slightly warm seat to go and investigate the main flight information board that is always placed in such a way that you have to walk over to read it? I'd better finish this blog post first.

I'm going to Sydney to defend the saltwater crocodile. It's another documentary dealing with a crocodile attack, and it's apparently my job to describe the motivations behind the attack from the crocodile's perspective. The victim is Jeff Tanswell, a fine bloke who we met last year in Darwin, introducing him to a crocodile for the first time since one bit him on the head while he was snorkelling off Thursday Island. I get the impression that Jeff quite likes crocodiles, except when they bite him on the head. So, the show in question wishes to reconstruct the attack (again) and it's my job to ensure that they represent what happened accurately. And that means defending the crocodile, because the natural assumption is that the crocodile had some kind of evil intent in its attack. Jeff realises that this wasn't the case, so let's hope that I can convince the production company. I don't think that should be difficult, because the concept that a crocodile is "just human" (if you'll forgive the extremely suspect analogy) and was only being "a crocodile" (to contradict my own analogy within the same sentence!) should be and - indeed - is more interesting than the notion that it's simply a toothy killing machine interested only in biting heads.

But ultimately I have very little control over the finished product. I can only hope that my interview and Jeff's detailed account are both integrated into the final reconstruction. It is not always the case with these things. Having done a lot of reconstructions for various production companies over the years, there is a tendency to push things towards the dramatic at the expense of the accurate. Now I'm all for getting people to watch and learn through devious means, but I strongly believe it can be done without compromising the facts. When it comes to crocodile attacks, we owe it to the victims - and the crocodiles - to get the facts right.

Sunday, July 13, 2008

Attacked by a crocodile while editing a film

Ok, that deliberately provocative title should not be taken at face value! However, I figured that "Cleaning the croc pool and doing some NLE" perhaps wasn't quite so exciting. But yes, it's all true. Today we decided it was time to clean the underwater filming pool, as we have a film crew using it next week. Cleaning involves attaching a long hose to the pump, setting it to waste, and sucking out any leaves and other detritus that has accumulated in the filming room. If we didn't do this, entering the water would stir up sediment and reduce visibility a little too much.

Cleaning is much easier on scuba, so tanked up I got into the water and started to clean. Smaug, our large male crocodile, wasn't too impressed by all this banging and splashing that I was doing and came across to investigate. It's quite a shock, even now, to realise that your face is about half a metre from a steel barrier behind which a very large crocodile is studying you intently. I noticed he was attracted to the bubbles that I was exhaling, and hence he was following me round. It didn't take long before his curiosity got the better of him and he struck at the fence with a loud clang. Underwater, a loud clang sounds more like someone dropping a pin on the floor. At least, to insensitive humans such as myself. However, with my face mere inches from his crashing jaws I was in no doubt what was going on! For just the briefest moment, I found myself wondering what I was doing. There I was, 2 metres under the surface with a 4.5 metre (14.5 ft) saltwater crocodile trying to get at me. The only thing separating us was a steel mesh barrier. A very strong one, it must be pointed out, but the feeling of being in the wrong place at the wrong time is a hard one for your mind to shake off.

Of course, it all looked absolutely spectacular and I wished I had an underwater camera with me. That is, naturally, the entire point of the facility. It is a completely unique way of seeing saltwater crocodiles. The fish swimming around my head didn't seem too impressed, though - they were more curious what on Earth I was doing down there too. By this time the floor was clean and I was getting cold. Next time I will persuade the film crew to avoid coming at the coldest time of year!

As for editing the film, well that all seems rather mundane after that little story. But we're pretty pleased with it. It's a 3 minute short film about crocodiles, with music and sound effects but no narration. There are sumptuous images of crocodiles and habitats that we filmed in DVC PRO HD late last year, and it's all coming together very nicely. I wrote the music in a few hours, but the biggest challenge was matching it with the images. Our NLE software isn't really equipped for music synchronisation, so I did it the old fashioned way. Anyway, it has reignited our appetite to produce longer films, without a doubt. It also justifies the purchase of our new plasma HDTV because, frankly, it looks stunning on there. It will soon be on display running continuously on multiple HDTV screens at Crocosaurus Cove, which will be great to see.

Sunday, June 29, 2008

Oh look, a crocodile!

There's a new tourism facility opening in Darwin very soon called Crocosaurus Cove. It might sound like a great place to lie on a beach towel and soak up the sun while giant reptiles wander past, but it's actually going to be the equivalent of an aquarium for crocodiles. Big crocodiles - we're talking 18 footers here. And Big Gecko was contracted to assist with moving them from the Darwin Crocodile Farm into the new facility, situated in the middle of town. Don't worry, there will be pictures to come but for now I should relate a cautionary tale about driving large crocodiles down the highway on a Saturday! It's the kind of activity that can be extremely hazardous, but not for the reasons you might think. Catching and transporting the crocodiles is a piece of cake really, but getting one down to highway into the town centre without causing a major accident? Now that's quite a job! People nonchalently overtaking in the right-hand lane would suddenly realise they were overtaking a trailer holding a very large crocodile, slam on the brakes, and fumble around on the back seat for their mobile phone camera so they could show the kids, all while weaving around wildly. When they weren't taking their eyes off the road, their passengers were winding the windows down to gesticulate towards the crocodile in case anyone had failed to spot it. We even had cars slowing down in front of the towing vehicle, causing our driver to overtake just so they could take a photograph as it passed them.

And people think crocodiles are dangerous...!

Friday, June 20, 2008

Sim Croc

I used to love playing Will Wright's simulation games when I was younger. I spent hours on Sim Ant, Sim Life and Sim Earth, all of which offered a fascinating if somewhat limited simulation of the subject matter. They become more sophisticated over time, and now Will Wright is putting the finishing touches to Spore - a game that enables you to take a single celled organism, evolve it into a multicellular creature, build a tribe, a civilisation, and eventually colonise other planets. It all sounds like an overly-optimistic exercise, but I'm looking forward to how it turns out nonetheless.

The first taste of the game was released a few days ago in the form of the Spore Creature Creator. As a zoologist I couldn't resist. You start off with a basic body and spine, and the ability to change its shape, add limbs, sense organs, weapons and other bits and pieces. After mere minutes you normally end up with a living, breathing digital creature that you can take for a walk around a small arena, activating a number of behaviours to show it off. It's a prelude to the main game, but it's no doubt a complete game in its own right. The power of the editor is remarkable, and the way the game interprets your creature and makes it move is impressive to say the least.

It really is a zoologist's dream come true - the ability to create whatever creature you want, to act like a digital God. There are limits of course, this is a computer simulation and not life, but the exponentially expanding Sporepedia of life shows just how incredibly flexible it can be.

Naturally, my first inclination was to create a crocodile. Frankly, it turned out a bit flat because I hadn't figured out how to manipulate the body properly. I won't even assail your poor eyes with it! My second attempt, however, was much better. Of course, I took some liberties with the crocodilian form and ended up with something more akin to an endearingly cute crocodylomorph / dinosaur hybrid. There's a picture below, followed by the .png file so you can import it into the Creature Creator if you want to play around with it.

Thursday, June 19, 2008

Tempus fugit

I seem to be missing the whole point of this blog thing! It's all about rapid updates, about sharing thoughts and snippits of information that might not otherwise be particularly newsworthy - a glimpse into my psyche, I suppose.

So it doesn't really work when it's been two months since the last update! How am I supposed to create an audience? Ok, let's try this again. This time I promise to regale you with all kinds of bits of useless information, and hopefully a little bit of useful information too.

I recently came back from Bolivia, where I attended the 19th Working Meeting of the Crocodile Specialist Group. The CSG is an IUCN-SSC (ie. Species Specialist Commission) group, essentially made up of volunteers who are invited into the group because they are significantly involved in crocodiles: conservation, education, research, management, farming, that kind of thing. Every two years there's a working meeting where the steering committee meet and we have several days of spoken and poster presentations. Of course, the main value of these meetings is really meeting people, catching up with friends and colleagues, sharing ideas, and hatching plans for collaborations. Before I'd finished I'd been invited to just about every country in Latin America, and it must be said I can think of few better places to visit. Bolivia was my first visit to South America and it was a great experience, and not just because it was just so completely spectacular. Even coming into Santa Cruz from La Paz ensured that I was glued to the aeroplane's window totally gobsmacked by the spectacular views of snow-clad mountains with clouds spilling down their flanks.

Anyway, I'm sure I'll write more about this later. I have to keep these short and sweet so that I have incentive (and time!) to keep writing them. Sometimes you get so busy that you completely forget where the time has gone.

Wednesday, April 16, 2008

Truth in the Media

Ah, don't we love our local newspaper the Northern Territory News! They do try, but occasionally I'd like to strangle (figuratively of course) the journalist who wrote the story. In this case we sent out a media release talking about the work we did with Sir David Attenborough in November 2006 for his excellent series Life in Cold Blood. After all, it was quite a momentous event for us bringing the great Sir David to the Territory to film our saltwater crocodiles (and I'm sure I'll write more about that experience later).

The original media release contains the following:

"David Attenborough is one of the only people I've met who actually exceeded my expectations" said Dr Britton. "His enthusiasm and fascination for both animals and people was humbling, and there's no better ambassador for how remarkable our crocodiles are than watching David enthuse about them in his inimitable style."

The NT News version was:

"There's no better ambassador for how remarkable our crocodiles are than watching David describe how magnificent they are," Dr Britton said.


They then go on to quote me saying that people come to the NT because it's a place that crocodiles eat people! First of all that was not a quote, and taken out of context of the media release (which is all about the value of crocs to the NT) it rather misses the point!

Oh well, keep trying...

Monday, April 14, 2008

Three cheeky monkeys, one crocodile

Just got back from the Darwin premiere of Black Water, not a film about rogue security agencies in Iraq but rather a crocodile thriller set in the Northern Territory. As you can imagine, the crocodile featured in the film wasn't interested in tea and biscuits with the cast. It is the latest in a series of movies about killer crocodiles, but I reckon this was easily the best. Of course I may be slightly biased because I did a lot of work on the crocodile sequences for the movie!

The film is loosely based on a couple of actual crocodile attacks that occurred in the NT, but they are used as a premise to set up the situation. You might call it a situation horror film: what would you do if you were stuck up a tree surrounded by water containing an unfeasibly hungry crocodile? It's an interesting premise because it plays upon your fears: not knowing where the crocodile is, nor what its motives are, and not really knowing what to do. And although the crocodile behaviour ends up being a little unrealistic by the end of the movie, it was certainly effective. Of course, I'm a sucker for films that take their time to establish atmosphere. I'm not a fan of most modern "horror" films that mistakenly believe that gore is a substitute for generating tension, and in that sense Black Water is quite old-fashioned.

We ended up doing most of the crocodile effect shots for the film, and I was intrigued because the director wanted to use real crocodiles instead of CGI. Perhaps that was a question of budget (Black Water cost $1.2 million Australian dollars) but it turned out for the best - there's no question that the effects look an order of magnitude better and more convincing than any CGI beast, because the crocodile was in control of its movement and not a computer animator. I've long been frustrated by how crocodile effects have been handled in movies, so what better way to show how it should be done than turn to the experts themselves - saltwater crocodiles. Our job was to get footage of the crocodiles doing what was in the script!

Most of this was simpler than you might think if you use the right approach - understand each individual crocodile, know what its strengths are, and encourage it to perform the right behaviour. It's a case of working around the animal, and adapting to what it wants to do. Of course, the director had such a low budget that we had to cut a few corners. One sequence involving a crocodile climbing into a boat could have been done by training the crocodile - something we've done several times in the past - but that takes time. Instead we had to improvise, encouraging the crocodile to run down a bank into the boat rather than climb over the side. And getting it out again? Why, just tip the boat! With a bit of creative editing it ended up looking quite convincing.

In fact, the end result looks so convincing that I've seen reviewers who couldn't tell whether we were using real crocodiles, CGI or models. Of course, the actors were mostly acting against a blue screen so that the crocodiles could be digitally inserted later, but it's real croc behaviour on screen and not an animator's idea of croc behaviour. A lot of these techniques come from years of working on natural history films where you need to understand the animals in order to know how, when and where to film them.

Things didn't always go to plan, though. The director wanted a specific shot of a crocodile launching itself towards camera left, jaws opening. We knew the crocodile that would deliver this shot, so we used a chicken to entice him towards us. The camera was housed in a protective case which was suspended near the chicken. I did warn the camera operator not to get too close to the head or the casing might get bitten. Too late. The crocodile took one look at the chicken, then one look at the white camera housing that was twice the size, and figured it would go for what must have looked like an enormous chicken! Crunch! The croc punctured the housing in several places and dragged it off its mount into the water. Fortunately the camera operator whipped it out of the water by its cable before the crocodile could find the soft, chewy centre. Scratch one very expensive casing, but it did get them a far better shot that ended up in the film.

Black Water has already opening theatrically in the UK, and it's available in the US on DVD, and finally now opening in Australia theatrically. It's definitely worth watching if you want to see real crocodiles on the big screen.

Wednesday, April 09, 2008

Antibiotic factors in crocodile and alligator blood - Part 1

In response to the discovery this week by Dr Mark Merchant (McNeese State University) that American alligators have powerful antibiotics in their blood, I've decided to write a short history of our research into crocodile blood and the discovery of the antibiotic "crocodillin" back in 1998. It's an eventful tale, so in the nature of all good cliffhangers I'm going to split it into at least two parts. Or perhaps that's because I don't have time to write the whole thing at once!

So, let's travel in time back to 1998 (don't worry, we're not staying forever). I was involved in a research project that I thought would have major repercussions around the world, because what we discovered was potentially ground-breaking. I was approached by BBC Science to suggest an interesting research project that they could fund, and film. Did I have an interesting project, oh boy!

I had long been intrigued by the immune system of crocodiles, having seen numerous examples where they generously gave each other some pretty horrific physical injuries - slashes and gashes exposing muscle and bone, ripping off legs, and biting off tails. Just a typical night down the swamp. And yet I couldn't recall ever seeing such wounds become infected. Put yourself in the same position: you've just had your arm bitten, you're lying in filthy water full of bacteria, and you just know it's going to get infected and you might even lose your arm. Not so with crocodiles.

What was it about crocodiles, I wondered, that gave them such potent immune systems? And was it something we could use in human medicine to treat our own disease?

The BBC Science producer, Jill Fullerton-Smith, wasn't particularly interested in this at first. Perhaps it didn't feature enough heads being ripped off wildebeests (the usual staple of TV documentaries about crocodiles)? Or perhaps she needed time to think about it? Yes, that was it. In fact, she apparently woke up one night a couple of weeks later, sat bolt upright in bed, and realised what a great question it was!

So a few months later with a BBC camera crew in tow, we started catching both captive and wild crocodiles to get a few ml of blood. We invited a few "celebrities" along to make the show more exciting (as if a British guy catching crocs in northern Australia wasn't exciting enough!) and sent the blood across to Dr Gill Diamond in New Jersey. I remember suggesting Gill because I'd recently read about his work looking at Komodo Dragon blood, investigating why those lizards with particularly unsavoury saliva didn't infect each other during fighting. He'd developed a technique to fractionate serum into its constituents for amplification and analysis. In short, he seemed like the ideal person for the job of looking at our crocodile blood. After preparing the samples and sending Gill red blood cells, white blood cells (leucocytes) and serum, we crossed our fingers and waited. We actually had to send the samples a second time because the courier company screwed up and let everything defrost and rot. Good job we only sent half the samples in case of such an event!

A few weeks later I was sitting in my office and the phone rang, it was the BBC producer Jill. I could tell she was excited. Gill Diamond had isolated the active constituent in the blood and tested it against a range of bacteria - it killed them all. He then thought he'd try for the jackpot and tested it against MRSA (methycillin-resistant Staphylococcus aureus) otherwise known as Golden Staph - resistant to all known antibiotics.

The constituent in the crocodile blood killed the MRSA bacteria.

I don't think it hit me straight away just how exciting it all was. I think Jill was expecting me to dance around the room punching my fists into the air, but perhaps it was my combined British reserve and scientific scepticism that kept it in check. For a while at least.

The results of our exploits were shown in the BBC documentary "Secret Life of Crocodiles" (also known as "Crocodile Secrets" on the Discovery Channel).

Gill's team and I were able to present these findings at the IUCN-SSC Crocodile Specialist Group meeting in Florida in 2002, and the abstract appeared in the proceedings:

Britton, A.R.C., Diamond, G., Laube, D. and Kaiser, V., 2002. Antimicrobial activity in the blood of the saltwater crocodile (Crocodylus porosus). [abstract presented by G. Diamond at the 16th Working Meeting of the IUCN/SSC Crocodile Specialist Group, Florida, USA, October 2002]

The saltwater crocodile shows a low incidence of infection from serious injuries sustained during intraspecific aggression, in spite of the microbe-laden environment in which it lives. This suggests a well-developed innate immune system, which provides a rapid, non-specific first line of host defense. In other aquatic species such as amphibians and fish, this defense is found in the mucous skin secretions as antimicrobial peptides. Due to the anatomy of the crocodile, we reasoned that a homologous defense would be found in the circulatory system, either as soluble factors or as agents expressed in phagocytic cells. To address the first hypothesis, we extracted serum from wild saltwater crocodiles to isolate naturally occurring antibiotics. The serum was maintained at -80C until fractionation. Serum was fractionated by Reverse-phase HPLC on a C-18 column with a 0-60% acetonitrile gradient, and fractions were assayed for antibiotic activity against E. coli in a modified radial diffusion assay. Preliminary results indicated strong antibiotic activity in several fractions. We have taken a single fraction, eluting at 13% acetonitrile, for further characterization. Based on our initial observations, we predict that the crocodile exhibits both peptide and non-peptide based antimicrobial activity in its blood.

In our next exciting episode, we travel forward in time to 2002 to meet Supercroc!