Friday, 27 January 2012

Tales of Scales and Scaly Tails

Possibly the cutest rat in the world? Bush Rat. Rattus fuscipes. Photo: Ryan Pearson
By Ryan Pearson
My recent trip into the wilds of Bauple was about more than just frogs and toads, in fact, the focus was more on other types of critters...the reptiles and mammals... and jeepers are there some similar looking and hard to identify varieties.  For the mammals we caught bandicoots, possums, mice, rats and a bunch of marsupials that look like mice and/or rats... but aren't. For the reptiles we caught monitors, goannas, dragons, geckos, and a heap of different varieties of skink. 

A Fawn-footed Melomys, a marsupial. Melomys cirvinipes. Photo: Ryan Pearson
The thing about small mammals is that a lot of them look almost identical despite being completely different species. Even across the marsupial vs rodent barrier, the similarities are uncanny. As with the frogs, the significance in in the details... but even more so for the mammals. To the untrained eye, many of these species would be lumped simply into the 'rat' category, but that is just not the case. For example, take the marsupial Melomys above and compare it to the rodent Eastern Chestnut Mouse below... could you spot the difference as it ran past you in the bush? I couldn't.
Eastern Chestnut Mouse, a rodent. Pseudomys gracilicaudatus. Photo: Ryan Pearson
Although, all is not lost, if you can get your hands on them, there are ways to differentiate. However, it does often feel like a game of 'spot the difference'. The bottom of the feet and the tail scales tend to be some of the most significant distinguishing features. A quick look at the tails of these two and it's obvious which one is which. Notice the patterning of the scales? The marsupial tends to have a more mosaic patterning to the scales, whereas the rodent Chestnut mouse has distinctly straight lines between each row of scales.

Marsupial vs Rodent tail comparison. Photo: Ryan Pearson

Another good way to identify the difference between small mammals is by scrutinising the bottom of the feet. As you'll see below the feet can come in various shapes and sizes, but the difference isn't always quite so obvious as this example. Often the feet can look very similar but the number and/or shape of some of the pads can vary making it a bit more difficult to identify.

Marsupial vs Rodent foot comparison. Photo: Ryan Pearson
That said, the painstaking identification process was undertaken for all of the small mammals and reptiles we caught, and these are some of the other critters we found...

Common Planigale with an ear parasite. Planigale maculata. Photo: Ryan Pearson

Open Litter Rainbow Skink. Carlia pectoralis. Photo: Ryan Pearson

Garden Skink. Lampropholis delicata. Photo: Ryan Pearson

Bush Rat. Rattus fuscipes. Photo: Ryan Pearson
Nobbi Dragon. Amphibolurus nobbi. Photo: Ryan Pearson

Skink. Lygisaurus foliorium. Photo: Ryan Pearson
Nobbi Dragon. Amphibolurus nobbi. Photo: Ryan Pearson

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