I finished my Masters of Science (MSc) at the University of Melbourne at the end of last year, and thankfully scored first class as did many of my good masters maties! I was looking at the goanna species Varanus varius and more specifically at the species phylogeography (wide-scale, historic gene flow), and its population / landscape genetics (small-scale, contemporary gene flow).
- Historic gene flow – mtDNA analysis of ND4 showed the presence of 3 clades within the species, separated by montane biogeographic barriers (Great Dividing Range (GDR) and Mcpherson Range), and possibly the Burdekin Gap in northern Qld (dry habitat barrier). Although I’m just finishing up some final lab work and analysis to reveal whether its the Burdekin Gap or a pattern of isolation by distance that has split the clades in this area.
- Contemporary gene flow – Microsatellite analysis indicated male sex-biased dispersal was present within the species (males move further than females), no significant genetic structure over the 600kms^2 that I sampled indicating the species is incredibly dispersive (can move large distances), and that there was a more recent area of contact between two clades at the Hunter Valley, NSW.
- Evidence from both these markers and their analyses also indicated that the species was more historically restricted to the north coast of Australia in QLD, and when the climate become more favourable (warmer/wetter) in the south they expanded southwards.
- I also found evidence that the species had used the Murray-Darling river system and its surrounding forest as dispersive corridors to spread west inland and south from QLD. (Amazingly, some individuals from the GDR in Qld were more closely related to individuals from near Adelaide and northern Victoria (2000kms west/southwest) than they were to individuals 50kms to their east in Qld. It’s thought that flooding events will have also facilitated the spread of individuals down these river systems.
Anyway, I thought I’d share some of the photos taken during my 2 year MSc project. So bring on the photos! I’ll chuck my 2 cents in on top of each photo. By the way sorry for the poor quality of the photos, a lot were taken on my iPhone.
So this is the beasty I was studying and chasing around in the field on several field trips throughout 2009, ’10 and ’11, Varanus varius aka Tree Goanna or Lace Monitor. They were often found running along the sides of roads as it is easy terrain for them to walk on, or running around camping and picnic grounds.
I went on 3 field trips out to East Gippsland and Wilson’s Promontory, Victoria, Australia, where my supervisor had already been trapping for 2 or 3 years and had other MSc students doing their research on other creatures. I also went on a 2 week long field trip starting in Brisbane, Qld and drove down the east coast of Australia through NSW and into Victoria to try and fill sample gaps where museums had not collected genetic samples previously. I did pretty well, but often saw many more than I caught each day… Damn goannas were incredibly fast and quick to run up tries and evade us weirdos running around with dog noose polls.
Here are a few photos of the places and habitat I was trapping/catching these guys in.
The first 3 photos are from Wilson’s Promontory
The rest of the photos are from various locations along the coast in NSW.
At the time of the field trip down the east coast many areas of Qld and NSW were suffering those severe floods. The below are photos taken at Nymboida Pub, NSW.
This was the scene behind the pub, usually a small creek.
These were the 2m long aluminium traps I used to capture the goannas. They were a simple trap that just had a trap door held up by a pin that was attached to a wire running to the other end of the trap and inside it was tied to some chicken. When the goanna pulled on it the door shut and it was trapped. I also hung future baits from a tree nearby to fester up and send the smell off into the surrounding bush to attract them. Unfortunately they’d also attract things like wasps, one time in Wilson’s Prom a bag had 100s of European wasps all over it and in it eating the chicken… bastards!
Sand pads were also left outside the traps to see if goannas had come to check the location out but hadn’t triggered the trap. I also set up camera traps outside the aluminium traps at Wilson’s Prom (left side of the below photo tied to the tree).
This was a boy I caught near Newcastle, NSW. Once caught I duct taped their mouths and legs together to prevent the goannas hurting us or themselves while I measured them, weighed them and took blood samples from them for the genetic work.
Another big boy being measured out in East Gippsland.
I’d also take measurements of the head size, this one below has just had its snout taped and is about to be measured.
I’d use a syringe to take a blood sample from each individuals caudal vein/artery in their tail situated just below their spine. It took a while to get used to it but eventually I could do it within a few seconds.
Lizards would also be weighed. Although they are a sexually dimorphic species you couldn’t tell the females from the males if they were below 4kgs. Males were the only sex that grew past 4kgs, sometimes reaching up to 12kgs if they lived near a tip or camp site where food was abundant. This one below is on the smaller side so could have been either a male or a female.
Occasionally they’d be kind enough to hock up their last meal in the aluminium traps. The photo below is from the individual caught at Newcastle (pictured above). That camping spot had literally millions of cicadas pretty much screaming their calls constantly, so it was no surprise when this guy’s stomach turned out to be full of them, and a bit of fur from a possum.
These two photos below are of an individual from East Gippsland that had somehow managed to eat a juvenile echidna, spikes and all, and then been able to vomit them up?! That cannot have been pleasant at all…
While in Newcastle on the field trip we also hooked up with some of my supervisors scientist friends who were working on the biomechanics of varanids’ skulls and their bite force. They’d set up about 5-6 digital cameras in a semicircle around the individual to get a 3D image of its head, and then test its bite force using a pressure sensor. However, the one below wasn’t too interested in biting down as I suspect it was tired and had had enough.
See those bloody claws?! They use them for climbing trees, and most probably to tear at and hold carcasses they find while pulling flesh off them with their jaws. Here’re some closeups of the claws… epic talons! I was scratched quite a few times.
I often had to go to some extreme lengths, or heights rather, to capture some of these sneakily evasive goannas. They’d often climb straight up the tree at the first sight of a human and into the very thin branches at the top of it.
You probably can’t see it but there were actually 2 big males in the tree in the below photo. My mate and field assistant, who also was a freak rock climber, would happily tear up their trees bare hand with the noose pole to get the samples and data I needed! To attract these guys below we had by chance come across a dead wallaby and pulled it away from the road and under this tree where we tied it so it couldn’t be moved. When we showed up though there were 3 of them, one bailed before we were out of the care and the other two went straight up the tree. We got them both though muahahaha!
When letting them go I’d place them on a nearby tree so their claws were otherwise occupied with a grip and wouldn’t scratch me once I cut the tape. Then while holding the body against the tree with its freed limbs grabbing the tree trunk I’d take the tape on their snouts off. Often they wouldn’t move an inch and would just sit there pretending to be dead while you walked off.
Here are some more photos of the goannas we saw, and sometimes caught, on the road trip down the coast.
My supervisor and his son with one of the largest goannas caught in East Gippsland.
Some other herps I got to see on my trips. Feel free to tell me what the species are if you know them as I haven’t bothered to look these guys up yet.
A friendly little venomous surprise was waiting for me under a leaf in a pit fall trap bucket one morning, wasn’t keen to get him out by hand…
However, this guy below I was brave enough to pick up and have a better look at.
And non-herps. These are what I’ve always known as ‘spit-fires’ because if you touch them they spray some nasty chemical on you that burns like hell. Happened to me once as a child in the playground at school, since then I’ve never been done!
Eastern Grey Kangaroos at Wilson’s Prom.
If for some reason you’d be interested in reading my thesis I’m more than willing to email it out just send me your email 🙂
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