RoboCroc

[from Darren: your comments were all filtered as spam because you used three urls in each. If you use MORE THAN ONE url, the ScienceBlogs spam-filter quarantines your message. Sorry, nothing I can do about this. I always publish honest comments as soon as I see them.]

Gators get hit on the road a lot in Florida. Like all large bodied reptiles (and by large bodied I mean bigger than say a leopard gecko) they tend to have low recruitment, late age of maturity, and therefore require low adult mortality for population persistence (~95% yearly adult survivorship for northern populations of several species of turtle, less for those further south). That means that for reptiles road mortality can be a huge concern (or in many cases the main factor in population extinction) unlike for many mammals like raccoons for which road mortality is perhaps grisly and tragic but not a particular source of conservation concern. I don't have any numbers for gators or crocs though. I would imagine that they are not as badly off as turtles since they don't tend to nest on the shoulders and they are easier to see and avoid (or more likely to damage cars, a deterrent for the douchenozzles that purposefully run over animals on the road). Anyway, there is some research on this, and a paper that comes to mind compared Snapping Turtle and Painted Turtle populations in wetlands in high vs low road density areas. In some high road density sites the population of Snapping Turtles was >90% male. Unfortunately the sample sizes were small so the CIs aren't very tight. Painted Turtle ratios were less affected but my own observation is that male painted turtles get hit quite often too (last year most of the DOR Painteds that I found in my haphazard wanderings were male). Here is a more general article on the problem of turtle road mortality.

Here is paper discussing an important point source of road mortality in Florida. Matt Aresco's work on the Lake Jackson ecopassage is quite well known within the circle of people who know about such things.

Huh - I never realised Irwin had an academic publication record. Which brings up the obvious question - how does one integrate the word "crikey" into a peer-reviewed article?

Probably the easiest way would be to put it in the title: "Crikey: Large Crocodylus porosus survives despite significant lower jaw loss." :)

I'm guessing that "Memoirs of the Queensland Museum" is only lightly peer-reviewed, however.

Aren't crocodilians attracted by the excessive heat generated by the asphalt on roads during a hot day? It would certainly help explain the nature of vehicular accidents with crocodilidans and other ectotherms.

Yeah, he has a few of them. I know he's published a fair bit on varanid breeding. His final publication was in PLoS ONE, on homing abilities in saltwater crocs.

Read, M.A., Grigg, G.C., Irwin, S.R., Shanahan, D., Franklin, C.E. 2007. Satellite Tracking Reveals Long Distance Coastal Travel and Homing in Translocated Estuarine Crocodiles Crocodylus porosus. PLoS ONE. vol. 2(9): e949 (5 pgs).

I wish the croc the best of luck on recovery. I hope Douglas Mader will do a write up on his work, if successful, and how the wound heals up.

Aren't crocodilians attracted by the excessive heat generated by the asphalt on roads during a hot day? It would certainly help explain the nature of vehicular accidents with crocodilidans and other ectotherms.

This is more a truism for small ectotherms. This croc was 3 meters, which would make a SA/V ratio that's not very useful for conductive heat acquisition. Besides, it was Florida. Barring winter, a Floridian night can hardly be considered cold.

I'd say it was more likely that the croc was crossing when the vehicle came by, and the animal decided (unwisely) to stand its ground.

Which logically leads one to question what kind of vehicle hit this animal, what kind of damage did said vehicle withstand, and what kind of driver sees 3 meters of crocodile on the road, and just presumes to "drive through?"

Yeah, it's all too little known that Irwin could indeed turn his hand to technical output: I mentioned this when I heard of his death (Tet Zoo ver 1, here).

Harlan wrote...

I'm guessing that "Memoirs of the Queensland Museum" is only lightly peer-reviewed, however.

So far as I know that's not accurate, nor (sorry) is it fair to make claims such as this.

>>"Which logically leads one to question what kind of vehicle hit this animal, what kind of damage did said vehicle withstand, and what kind of driver sees 3 meters of crocodile on the road, and just presumes to "drive through?""

Unfortunately I've heard of a lot of worthless jackasses who TRY to run over snakes they see on the road, I'm sure there are some really dumb ones who would also try it with a croc.

Unfortunately I've heard of a lot of worthless jackasses who TRY to run over snakes they see on the road, I'm sure there are some really dumb ones who would also try it with a croc.

There was a study done on the Long Point Causeway which is in southern Ontario at Long Point that extends into Lake Erie. It has been ranked as one of the worst roads in the world for roadkill (although the sampling of roads is not obviously very complete). They found that about 3% of drivers will hit a snake or turtle on purpose. Unfortunately on a moderately high traffic road like the Causeway this translates into a life expectancy of on road turtles that is less than the time it takes turtles to cross the road. Based on blatant stereotyping I would suggest that the percentage is higher in most areas of the States.

That is VERY unfortunate. Their instincts to warm up has, sadly, led to their injuries. I'm glad we're doing as much as we can to make up for it. Normally, I say leave nature alone, but this is a special case. That first comment about Steve Irwin is understandable, but, somehow, doesn't seem to be appropriate. I'm worried about this problem with Crocs.

Here's another part of North America that is basically a killing ground for plenty of creatures:

http://www.lakejacksonturtles.org/

...We have the technology. We can rebuild him.

Anyway, quite an interesting article Darren. Shame it was an American Croc, they are quite rare in Florida, endangered as all get-out. But you are right, crocs are tough little buggers, and they can survive injuries that would easily kill or incapacitate a human. Just goes to show you how bad-ass archosaurs are (in addition to who whole fact that birds can thrive in low-oxygen enviromnents while we mammals choke for breath), despite how little credit they are given by the (for now) mammal rulers of Earth.

I read (where?) about a study that involved placing rubber snakes on the road shoulder to see how many would swerve to hit them. One policeman swerved to run over it, then backed up to run over it again, and finally got out of his car and shot it with his service revolver.

I guess some people just have it in for rubber animal figures.

'Which logically leads one to question what kind of vehicle hit this animal, what kind of damage did said vehicle withstand, and what kind of driver sees 3 meters of crocodile on the road, and just presumes to "drive through?"'

Speaking as somebody who loves animals but also drives a lot: in rainy night, you may simply not see 3m long crocodile. If you have driving licence, you know what I mean. Also many animals have suicidal habit of crouching until the last moment and then trying to run away on the road in front of the car.

About a driver - only an idiot would try to run over animal on purpose. Even if you don't care about animal, even a small animal can cost you lots of $$$ in damage. But if you see anything smaller than an elk on road - don't swerve, brake and go forward! Risk of serious car accident when swerving is very high.

Which reminds me of a curious story. Apparently people in Botswana live in fear of driving over a snake crossing dirt road. Apparently snake, attracted by the heat, is able to climb into the machinery or a car driving slowly over it, and then biting the driver when he eg. checks the engine.

I'm guessing that "Memoirs of the Queensland Museum" is only lightly peer-reviewed, however.

On the contrary, Memoirs of the Queensland Museum has a very good reputation. I've considered submitting an manuscript there, and my eventual decision to submit elsewhere was based solely on the fact that the journal is not yet available online, not on any complaints with the journal itself.

Damn! The Unclosed Blockquote Imp strikes again!

I agree with Darren, it's pretty unfair to talk about people like that. Shame on you!

If you use MORE THAN ONE url, the ScienceBlogs spam-filter quarantines your message.

Sometimes! Sometimes the limit is two, and on rare occasions it's somewhere higher. There are things eldritch entities out there that man was not meant to know!

They found that about 3% of drivers will hit a snake or turtle on purpose.

Having a phobia of snakes I can understand, but why kill a turtle?!?

"I'm guessing that "Memoirs of the Queensland Museum" is only lightly peer-reviewed, however."

Hey, be nice. I agree with Tim Morris and Darren, shame on you for blasting a journal and someone who publishes in it just because of their reputation in nature documentaries. I mean, that would be like judging Horner's entire career on his extreme stance in the whole "T-rex, hunter or scavenger" debacle.

But on the subject of the "Lake Jackson Turtles" site, if the problem is so bad both for the wildlife and the motorists, why doesn't anyone do anything about it? Not just for the turtles, snakes, and gators, but for the wildlife themselves. People can get hurt in wildlife collisions; a panicked deer is strong enough to tear off a car's side mirror, and one could easily get in an accident by swerving to avoid a deer or an alligator and hitting another person's car instead.

Of course, the real question is how do we convince wildlife to use the eco-passages, rather than just running across the road as normal and playing dice with fate.

But on the subject of the "Lake Jackson Turtles" site, if the problem is so bad both for the wildlife and the motorists, why doesn't anyone do anything about it?

In this case, they did. There are drift fences and volunteers have been helping to move the turtles to the other side but of course this is a temporary solution.

the real question is how do we convince wildlife to use the eco-passages

This is the problem. There are solutions but they are expensive. The basic idea is that some sort of drift fence or equivalent structure is necessary. It is relatively easy to build a simple drift fence, the difficulty is in making a system that will function without maintenance for decades ('cause you can be sure that there will be no funds allocated to maintenance). A well designed fence funnels wildlife through the tunnel. The ideal system would probably be close to what has been implemented at Payne's Praire. There is a picture here if you scroll down. I have visited this spot recently and it is very cool. The amount of wildlife just adjacent to the road is incredible. Even though it was dry my friends and I saw about 20 snakes (3 species) 10 or so gators, 1 softshell and maybe a dozen Pseudemys all right next to the road just doin their thing in their habitat. In most highway situations populations of amphibians at least are depressed or extirpated in adjacent habitats (Lenore Fahrig's lab at Carleton U has done some work on this). Other improvements include builing bridges instead of tunnels, making tunnels as large as possible, and installing grates in the road above to increase light and air circulation.

Anyway, road engineers are notoriously resistant to spending any money or effort to do anything at all for wildlife. A lot of the projects that do exist in Canada have been built with ungulates in mind and framed as a safety issue. An ecopassage may cost 10s of thousands of dollars, a tiny fraction of the cost of the road, but it is too much for them to contemplate in most cases. Also, some members of the public may be resistant. There was an active campaign against the Long Point ecopassage project by some local people. Even though the funds came from outside sources they spread false rumours that it would make their local property taxes increase. They even complained that the project would remove the trees lining the causeway even though a) the trees are non-native hybrid poplars, b) near the end of their lifespan, c) do not form a neat row anymore since most have died or been removed already, c)do not ensure the structural stability of the road as claimed, and e) most will not be removed anyway. I think that some of these people are simply ideologically opposed to anything progressive and they don't understand the difference between conservation objectives and animal rights objectives. Somehow in their paranoid Stephen-Harper-voting good-old-boy little brains they made the connection between not letting threatened reptiles go extinct and not being allowed to shoot ducks (a popular local pastime of economic importance). Anyway, there was no cost to the community, and a net bennefit (in terms of road safety and maintaining the ecosystem that supports the local eco-, fishing, and hunting tourism industries). Even with all that going for it, the project has taken years and has been touch-and-go. I don't have a lot of hope for projects elsewhere that have less clear anthropocentric benefits and less displacement of costs.

"crocodile called 'RoboCroc', he was expecting something that looked more like a scaly decepticon"

At the risk of seeming like too much of a nerd even for palaeo this decepticon did exist and was a Headmaster called, rather fittingly, Skullcruncher. For some reason as I recall he was purple however. Quite how a huge metal crocodile was supposed to disguise itself never really did make any sense to me even as a wee kiddie. Even better he had a companion that was called, I kid you not, Weirdwolf - no prizes for guessing what he transformed into!

"Unfortunately I've heard of a lot of worthless jackasses who TRY to run over snakes they see on the road, I'm sure there are some really dumb ones who would also try it with a croc".

Apparently the Vietcong took full advantage of the fact that American Tank Drivers did this sort of thing by burying Anti Tank Mines and curling dead Cobras on top of them....

Let me just repeat here that there is no solution to a problem in transportation that cannot be improved by the addition of a catapult. That is all.

"crocodile called 'RoboCroc', he was expecting something that looked more like a scaly decepticon"
Well, the original toy of Beast Wars-era Megatron was a crocodile.

There were several incidents of car-vs-croc in the recent Wet here in north Queensland, e.g. one survivor in Townsville (...Googling... Townsville Bulletin reports a 1.6 m freswhwater croc suffered "an injured eye, several broken teeth and gravel rash", plus "There was a big saltie run over by a taxi in Cairns a couple of years ago and another freshie was hit near the Bohle a couple of years ago as well") and one killed on one of the causeways across the Leichhardt here in the Isa. Another was killed a few years ago here and didn't get reported in the newspapers (but the QPWS wildlife ranger let me have it for the skeleton, which came up very nicely with dermestids and has helped identify a lot of fossils). On the same causeway, I'd picked up pieces of a good-sized Emydura a few days earlier (David asked "why kill a turtle?"... I imagine this one would have gone off with a huge POP!: there were bits of shell and limbs scattered over several metres of road, while it was still very fresh and very low traffic, probably only hit once). A few days earlier, a 14-year-old kid drowned at the same spot.
I'd forgotten there were freshies in Townsville: I'm pretty sure they're not actually native on the east coast, but have been translocated into the Ross River and do very well there.
[While mentioning recent events in Australia, I'll note that the death toll from the fires in Victoria has been revised downward from 210 to 173. Some of the missing turned up safe and well, and some had been counted two or more times by different witnesses or - like that turtle - from widely separated fragments. Still too many deaths.]

And for my 2c, Memoirs of the Qld Mus is a decent journal (though mostly 'in-house', and with the odd bit of editorial meddling that has annoyed me a couple of times), and is now gradually putting content online.

How about a TRUE robocroc? After all, I believe I've already seen robofish and a robosnake.

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