Tuesday, 18 January 2011

Tasmanian bouncers and egg-layers!

Our drive into the Tasman bush was almost as exciting on-road, as it was 'nearly off-road'...It seems that the accepted local driving technique on dirt-roads with many blind corners involves speed, lack of breaking, expletives, fist-waving and juggling of mobile phone...well, that's what many locals were trying to teach me via positive reinforcement. Each time a tell-tale plume of dust appeared ahead or behind us, I prepared myself for the spray of dirt, gravel and expletives.  Given I was nominated driver, I should have taken photos of the said driving, as I am sure photography could be added to the multitasking ability of Tasman road etiquette. One thing is for certain, the large number of road-kill at the side of every by-way was almost certainly a function of the Taman dirt-road driving code...or lack of one!

A Kangaroo watches us from a safe distance...away from the road!
As we headed north on the island to Mount William National Park, the roads became very narrow, this possibly gave the local wildlife a chance of getting across alive. This was not due to cars slowing due to the narrower, twisting roads, more to do with the animals having less ground to cover as they dash in front of oncoming vehicles...some, I noted on occasion, on the wrong side of the road (vehicles that is!). As we entered the Park we turned off the main dirt road towards the Eddystone Lighthouse, where a campsite was situated drawing many vehicles to this remote part of Tasmania. Off the 'main' dirt road, we slowed our pace to a crawl...in the vain hope we might see local wildlife...alive! We had been saddened by the sheer body count on the road, but slightly heartened by the fact that Tasmanian Devils would get a free meal...albeit the ultimate in fast food, else they too might join their departed meal.

A dark shape at the foot of the tree moved...
Looking for beasties in the Tasman bush initially reminded me of hoping to spy a Kiwi in New Zealand...you know they are there, but you do not stand in a chance of seeing one. Frustrating. Tasmania is different. If you stand still and remain quiet for a few minutes, the bush soon delivers up a bouncing pouched wallaby or suchlike. However, hiding in the shadows near our road was something that none of us expected to see...a monotreme! There are only two groups of monotreme left in the world, found both in Australia and New Guinea. They include the bizzarre egg-laying mammals, the platypus and echidnas, that are essentially like us mammals, bar the egg thing. They have an interesting evolutionary history, in so far it is very poorly known, with a few fossils from Australia in the Cretaceous. These Cretaceous fossil monotremes indicate this group radiated at least 70-80 million years ago...but surely there has to be earlier fossils? Alas, none have been found to-date.

We stopped the car and slowly approached the base of the tree and were greeted by a site we really did not expect. A ball of fur, spines and the pointiest nose you could ever imagine, perched on such a round animal. It was as if a golf tee had stuck itself to a golfball...a spiky golfball. This was our first and possibly last siting of an echidna. Often called the 'spiny anteater' this small spiny ball also supplements its diet with worms, insects, termites and am sure anything the right size that crawls within range of its long sensing nose.

Molecular studies of both the platypus and echidna suggest they share a common water-living ancestor, some 30-50 million years ago. Leaving a watery habitat at this time would have been a brave leap for such a group, given marsupials ruled the Earth...well Australia. Many pouched beasties would have been looking for similar ecological niches to occupy and share with the early echidnas, but it seems they managed to eek-out an existence in the face of such bouncy competition. It has been suggested that the echidnas egg-laying adaptation provided them the edge over the marsupial reproductive strategy. 

After a few minutes of watching the echidna, we all returned to the car with broad grins. Knowing that we had all had a close-encounter of a spiky, monotreme kind. Simply stunning. The echidna waddled-off about his or her business...am not sure how you might determine the sex an echidna?

As we drove further into the Park, the kangaroos and wallabys became less weary of our car...possibly because they did not recognise it as a car, given we were driving slowly, engine not screaming, and horn not blowing. As I spied a wallaby almost outside our car, I stopped. With a hint of guilt, we all snapped photographs of the shy herbivore, remembering the 'Wallaby Jerky' I had eaten in Sydney airport a few days earlier.

While many of us happily eat cow, chicken and pig...(ah, the memory of the CCP burger in South Dakota last year...yes, a CowChikenPig burger!), the thought of eating marsupial was initially odd. But I have also to admit, the night before we had all tried wallaby sausages and they were good! Gives a whole new twist to, 'One mans meat is another mans marsupial'....

For many years I have been fascinated by wallabys, this in part was due to a paper by McNeil Alexander on the elastic recoil he measured in the hind limbs of these hopping macropods (literally 'big-foot'). If it wasn't for the fact that they hopped, when seen at a distance...a long distance...you could be forgiven for thinking they have an almost dinosaurian body outline...until they move. However, as Bill Sellers, colleagues and I suggested in a paper last year...hopping might well have been in the locomotor repertoire of some bipedal dinosaurs! Even I, as a child, have been driven to hopping...usually in a school race! I'm not suggesting that dinosaurs hopped around the Mesozoic, just that they were capable of a hop, if the mood took them.

However, the limb and pelvic adaptations of macropods places them in a hopping league all of their own, with some of the larger kangaroos being able to reach speeds upwards of 40 miles per hour for the 200 pound red kangaroo (Macrpus rufus). This bounder can also leap up to 25 feet in a singe hop, but also clear a 10 foot fence...that's accomplished hopping!

By the end of our long day in the north west edge of Tasmania we headed back to Hobart and to the our hosts Andrea and James. Tomorrow, we had work to do...of a bunny variety. Alas, I cannot share this work with you, as its part of a research program of a colleague at Penn. However, I shall pick-up my Tasman tale with a brief look at some very, very, very old fossil wood!

1 comment:

  1. I'd imagine that some of the smaller Ornithischians could have been capable of hopping.

    What other dinosaurs might have been able of hopping? Do you have a link to the paper?