Archive for fauna

Australian Critter of the Week: Potorous gilbertii

Posted in Australian Animals, biology with tags , , on March 3, 2010 by cpolsonb

Well it’s Wednesday again and time for another Australian critter of the week. This week I’ve chosen an animal that is very precious to me as an aspiring conservation biologist in Western Australia. That little animal is the Gilbert’s Potoroo (Potorous gilbertii), a cute little marsupial with a tragic past and shaky prospects. Gilbert’s Potoroo were first discovered in 1840 and as you might expect are named after English naturalist John Gilbert. It was not long after their discovery that all trace of them was lost, and after a short while they were presumed extinct. Of course our story doesn’t ended there and out of the blue in 1994 a shocked researcher discovered what she later identified as a Gilbert’s Potoroo in a trap she had set for wallabies. Thus the extinct status of Gilbert’s Potoroo was removed, 120 years after they were declared so!

But the elation of rediscovering these cute little critters soon wore off as the critical plight they were in became apparent. Researchers struggled in vain to find a large breeding population of Gilbert’s Potoroo but to no avail. Historically the Gilbert’s Potoroo had very few predators, and those it did have were unable to follow it into the thick undergrowth of it’s habitat. Not so for introduced foxes and cats who while they hadn’t succeeded in wiping them out completely had successfully reduced the Gilbert’s Potoroo population to less than 50 individuals! Stack on top of this habitat destruction and disease and we’ve got ourselves one unfortunate little marsupial. Gilbert’s Potoroo has the ghastly title of Australia’s most endangered animal and is indeed one of the world’s rarest mammals.

In order to protect the remaining few individuals their location at Two People’s Bay was deemed a Class A nature reserve, meaning no unsanctioned humans are allowed to set foot within it’s bounds. This is course did not stop the foxes and cats from continuing their carnage and so in 2005 three specimens were translocated to pest free Bald Island. Since that time a few more individuals have been taken to the island in an attempt to establish a breeding population. Despite Biologist’s and Conservationist’s best efforts the number of Gilbert’s Potoroo surviving today is estimated at less than 40 individuals. This dis-heartening excerpt from the conclusion of a report by the Department of Environment sums up the plight of the Gilbert’s Potoroo succinctly:

Gilbert’s Potoroo is known from one population in the wild of less than 30 individuals. Its geographic distribution is precarious for the survival of the species. The species and its habitat are subject to a number of ongoing and potential threats including a catastrophic or uncontrolled fire, predation from foxes and feral cats, low recruitment of young to the adult population, the impact of the dieback disease caused by the root pathogen Phytophthora cinnamomi on fungi host plants and the clearing of areas of suitable habitat within the species extent of occurrence.

Next weeks won’t be such a downer I swear…

Australian Critter of the Week – Moloch horridus

Posted in Australian Animals, biology with tags , , on February 24, 2010 by cpolsonb

Moloch horridus or the “thorny devil” as it’s commonly known is one kick ass lizard. These little guys grow to around 20cm long and live throughout the scrub and desert of central Australia. We are lucky enough to have the highest density population here in Western Australia! As well as being used for defense and camouflage the thorny scales all over its backs contain tiny little canals that carry water to its mouth, how awesome! The thorny devil is also an example of convergent evolution; where genetically dissimilar species evolve similar characteristics. As it has been isolated geographically for many million of years Australia contains many interesting examples of convergent evolution. In the case of the thorny devil it has evolved physical, dietary and activity patterns similar to the North American Horned Lizard. Perhaps the cutest thing about the thorny devil is it’s unusual gait, involving freezing on the spot and rocking as it moves around searching for food (namely ants).

Another awesome thing about this little guy is that it actually changes its colour depending on the amount of sunlight in its surroundings. It also has the crazy little “second head” at the base of it’s neck. The use of this second head is still somewhat of a mystery although leading hypotheses suggest it may be used to confuse predators or even to store fat and water. Whilst not endangered they are protected under the Wildlife Conservation Act. Unfortunately they are sometimes killed on roads as they bask for sun and absorb the heat from the tarmac.

That’s all for this week!