Taking the bite out of crocodiles with CrocBITE

Crocodiles are neither evil nor malicious, but they do sometimes bite people. Photo Adam Britton

Today we (Big Gecko and Charles Darwin University) are launching CrocBITE, an ambitious project to archive all crocodilian attack incidents from around the world, the purpose of which is to improve our understand of human-crocodile conflict (HCC). HCC is arguably the biggest threat to crocodilian conservation now, a reversal of fortunes for those crocodilian species whose populations have recovered sufficiently to come into regular conflict with growing human populations. CrocBITE isn't about vilifying crocs; quite the opposite, it's about understanding risk factors, addressing conservation problems, improving human safety, and increasing respect (or at least tolerance) for crocodiles.

I wrote a piece for The Conversation which was published this morning, you can see that here. However, I thought I'd post the original version here. It doesn't contain half as much information, but it takes a slightly different approach and makes some valid points.

Can crocodiles use tools?

Smaug with hat, or devastatingly effective
camouflage? Photo by Brandon Sideleau.

A blog article over at Tetrapod Zoology (a site that you should bookmark and read regularly if you're not doing so already, because it's rather good) is running a story about tool use in crocodiles and alligators. Yes, that's right, tool use. We know that crocs are much smarter than people give them credit for, but are they really capable of using tools as well?

The article references a paper that's just been published digitally by Dinets et al (2013). They describe mugger crocodiles at the Madras Crocodile Bank appearing to balance sticks on their snout and sitting under nesting egret colonies. Egrets use sticks to build their nests, so they spot some floating in the water, land next to them, and get a nasty shock when they try and pick one up. The paper describes this as a deliberate attempt by the crocodiles to mislead the egrets into landing within striking range, with the sticks as the tools in the ruse. It's a compelling idea.

Seeing crocodiles with sticks, leaves and other vegetation balanced on their head isn't new, we've all seen them doing it. We have a large saltwater crocodile who lives in a pool covered with Fistia spp, an aquatic plant that makes a fetching hat when he surfaces underneath one. I suspect many of us have wondered whether this plays any kind of functional role, or whether it's simply the crocodile not caring either way whether it has plants on its head. I've seen crocodiles surface in such dense vegetation that they can't actually see, and shake their head to clear them off. Other times they seem to sit quite happily without apparently noticing. If you were a bird and saw a nice bit of vegetation and didn't recognise what was underneath it, you might think that crocodiles could learn to use this vegetation to increase their chances of catching prey. It's certainly feasible, but proving it is another matter entirely.

The Dinets et al. study suggests that mugger crocodiles only balance sticks on their head and sit under egret colonies during egret breeding season. This certainly supports the idea that something deliberate is going on, although it's still possible that it's incidental; perhaps the crocodiles spend more time sitting under egret colonies during egret breeding season, and those that have sticks on their heads might get lucky when an egret gets fooled? To counter this, the authors point out that the area around the egret colony doesn't have many sticks, suggesting that the crocodiles must bring them across to the colony for them to use as bait. Even if it is purely coincidental at first, crocs learn fast, and this might reinforce behaviour that makes sitting under a nesting egret colony with sticks on your head more likely.

I think it's a great observation, even though there's still a skeptical part of my brain wondering whether there might be another explanation. I'd love to see more work done on this, because a study like this opens up a whole set of really interesting questions. Science! What is true, though, is that crocodiles do some amazing and unexpected things, and it wouldn't surprise me if they were this cunning. We know that they're capable of it.

Dinets, V., Brueggen, J.C. & Brueggen, J.D., 2013. Crocodilians use tools for hunting. Ethology Ecology and Evolution, in press. doi.org/10.1080/03949370.2013.858276

CrocLog Podcast Episode 14

Ok, I admit, it's been a while. The last CrocLog Podcast was back in December, so it's been over eight months since the last episode. It's been difficult to find the time to record podcasts since the last one, not least due to family circumstances. Still, despite feeling really quite ill and Brandon feeling really quite tired, we managed to record Episode 14 back in June. I'm now back from a trip to Botswana, and so I've been able to put the finishing touches to Brandon's editing, and here it is at last. I'd like to think we can get back onto a reasonable schedule from now on.


In this episode we don't interview anyone, but you do get to hear us at our worst! Apologies for sounding half-dead, but it's better than being any more dead than that. Brandon and I have a good chat though about the recent Crocodile Specialist Group meeting that took place in Sri Lanka in May, we talk about Lolong's death, discuss the challenges in transporting giant crocodiles overseas, and Brandon brings us up to date on crocodile attacks and the progress of the attack database.

Links to the podcast below:

You can carry the entire Chinese alligator genome on a USB stick

So Zhejiang University scientists have finally sequenced the entire genome for the Chinese alligator (Alligator sinensis). This is a pretty big deal, and the first fully published genome for any crocodilian. Amazingly, the entire genome is a "mere" 2.3 Gb of data, enough to fit onto a cheap USB stick, or perhaps on your phone.

Why is sequencing entire genomes important? Well, the genome contains all the instructions on how to build and operate a Chinese alligator, with all of its accrued evolutionary innovations over hundreds of millions of years, everything that makes this species both remarkable and unique. It's all there, all we have to do now is figure out which instructions do what. The team behind this have already identified several interesting "subroutines", such as modifications made to haemoglobin to increase oxygen carrying capacity, genes responsible for immunity and the function of antimicrobial peptides that give their immune system such potency, and many clues to their evolutionary history. It feels a little like hacking an operating system, except one that's considerably more complex than Windows (and is far less prone to crashing). Besides, it represents another opportunity to point out just how incredible these creatures actually are.

I look forward to being able to upload the genome into an artificial life simulator on my PC to recreate a digital Alligator sinensis. Maybe not in 2013, but I'm sure it's coming.

Here's the full paper published in Nature:
http://www.nature.com/cr/journal/vaop/ncurrent/full/cr2013104a.html

What really killed Lolong?

Alas poor Lolong, we hardly knew ye. The largest living crocodile that any of us had ever seen is gone, a mere 18 months after he was caught. It's now been a little while since he died, the initial disappointment has passed, teeth have been gnashed and fingers have been pointed. Still, I'm repeatedly asked about what caused his death. We have the official necropsy results of course, although many of you won't have had the chance to see those. So just what killed the largest crocodile in captivity and could anything have been done to prevent it?

Seeing Lolong was one of those "once in a lifetime" events. He was a glimpse into the past, a time that's probably lost forever when truly massive reptiles lurked in the river. For many, Lolong's size was fearsome yet he was remarkably gentle while he was in captivity. Worryingly so, in fact. Of course, Lolong was accused of having killed and eaten at least two people, leading to his "most wanted" status in the first place. Nobody ever proved that Lolong was responsible for those deaths, although it's certainly quite possible and a reasonable conclusion. Despite this, his impact on the Philippines can be measured by their national response to his death, the mourning for an individual whose species is generally despised so much it is compared unfavourably to the nation's politicians. His iconic status did much to earn crocodiles (of the non-political kind) some respect.

A monster crocodile in Toledo

In late 2012, Toledo Zoo contacted our company looking for an adult saltwater crocodile for their forthcoming Wild Walkabout exhibit. They weren't looking for a particularly massive one, only about 4 metres (about 13 feet long). I figured we could do a bit better than that. It just so happened that I knew of an awesome 5.2 m (17 ft) saltwater crocodile that was whiling away the days in a muddy pool in captivity, an animal that had been removed under license as a "problem crocodile" from a landowner's property a couple of years earlier. What better role than as an ambassador for how awesome crocodiles are (and how many big crocs there are in the NT!) for Toledo Zoo? It didn't take long for Toledo to upgrade their ambitions, and so began the long process of arranging the transport of a massive crocodile halfway around the world. We've done this before several times, but each transport presents its own challenges. The main priority is to make sure the crocodile is happy and has a stress-free journey, something we've gotten down to a fine art. In fact the only issues were some last minute bureaucratic mix-ups, but these were sorted in the nick of time and it all went as smoothly as could be expected. "Baru" (as he is now known) is happily exploring his new million-dollar facility at Toledo Zoo. I think most of us would be quite happy with a million dollar home. So now you have an excuse to visit Toledo and visit Baru. The rest of the zoo is also very good, I was really impressed with some of the innovative designs and behavioural enrichment ideas that I saw, and their conservation breeding program is world-class (eg. Kihansi spray toad reintroduction).

Here's the news story that the Toledo Blade published which shows some of the transport and offloading process. They got a few figures wrong, including the fact that the journey actually took over 50 hours, not 30 hours. They also didn't mention the part on the 15 hour international flight where the captain announced to the entire passenger compartment that they were sharing a flight with a very large saltwater crocodile. There was audible gasps.

A Night for the Crocs

Adult Tomistoma, Photo (c) Soham Mukherjee

I should have posted about this earlier, but recent events have made the last few weeks a little hectic. This Saturday 16 February an event called "A Night for the Crocs" is being held at Zoo Miami in Florida.

There are all kinds of activities for kids and adults alike, and best of all the proceeds for the event will be used by the Tomistoma Task Force of the IUCN Crocodile Specialist Group for direct action to conserve the endangered Tomistoma (false gharial) and its peat swamp forest habitats in Malaysia and Indonesia.

I won't duplicate any more information from their website, so go and check it out here. Sounds like a lot of fun for a good cause, and you can't argue with that!

So long, Lolong

Sadly, Lolong the record-breaking 6.17 m saltwater crocodile caught in the Philippines in September 2011 died last night around 8 pm local time. There's a lot of speculation about the cause of death, but until a necropsy has been completed, we won't actually know what killed him. Ronnie Sumillar, the local expert who led the capture effort, is conducting the necropsy. I'm sure this is not what he wanted to be doing today.

I'll write a more detailed post when more has been confirmed.