Aiden Wright
Aiden Wright is a Field Ecologist for the Australian Wildlife Conservancy, based at North Head Sanctuary, Sydney.
Name: Eastern pygmy possum (Cercartetus nanus)
Size: Body length: 10cm, with a long prehensile tail that is often used as a fifth limb to carry nesting material back to hollows. Weight: 45g.
Diet: Primarily nectar and pollen, occasionally supplemented with fruit and invertebrates.
Habitat/range: Eastern Australia, including Tasmania; occupying heath, scrubland, eucalypt forest and even rainforest.
Conservation Status: IUCN Least Concern, listed as Vulnerable in NSW.
Superpower/Fun fact: When they need to conserve energy, they can enter a period of torpor where their body temperature will fall below 2°C!
As the name suggests, the eastern pygmy possum is a pocket-sized possum found in all Eastern states of Australia, including Tasmania. A fully-grown adult will often weigh less than a golf ball! In fact, it is uncommon for an individual to weigh more than 40 grams, unless they are a mum carrying the extra weight of pouch young. Mums typically carry four young in the pouch, which become independent at 10g, although some occasionally decide stick around for longer, even after reaching 20g (perhaps to the dismay of mum). The species will shelter in hollows, under loose bark, in grass-tree skirts, in abandoned birds’ nests and in ringtail possum dreys.
Eastern pygmy possum, Pilliga National Park, NSW. Credit: Australian Wildlife Conservancy
Eastern pygmy possums primarily feed on the sweet nectar of banksia, eucalypt and callistemon species using their specialised brush-tipped tongues. These nocturnal nectar nabbers get to work after dark, after the daylight pollinators (such as birds) have finished up for the day, ensuring their food plants receive round-the-clock attention. After burying their faces into these flowers to access the nectar, their dense fur accumulates pollen, which is then transferred between flowers.
The eastern pygmy possums have a prehensile tail that acts as a fifth limb, gripping to branches as they navigate the canopy and understory in the search for food. Their adept climbing abilities, combined with their low weight, allows them to access flowers that are often out of reach for larger species. In doing so, they help to transfer pollen between flowers that may have otherwise been missed. These feeding behaviours highlight the important ecosystem services that eastern pygmy possums provide, with some suggestions that these pocket-sized pollinators are more efficient at pollinating some native plants species when compared to birds and insects.
In some environments, eastern pygmy possums may not have year-round access to flowering plants, which presents a challenge for this highly nectar-dependent species. To overcome this, the possums supplement their diet with fruits or insects. They can also enter periods of ‘torpor’ to conserve energy, which is also an important strategy during the cold winter months. During bouts of torpor, which can last for more than 30 days, their body temperature will fall below 2°C and their metabolism will slow by up to 98%.
Fire plays an important role in the flowering patterns of the environments where eastern pygmy possums like to feed and frolic. Inappropriate fire regimes and wildfires can remove the floristic diversity that the species is dependent on, whist altering the availability of safe nesting sites. The possums are also susceptible to predation from cats and foxes, with the combined effect of these threats having led to local extinctions in some areas. In 2016, eastern pygmy possums were reintroduced to North Head Sanctuary in Sydney, where they have resumed the important process of pollinating the Eastern Suburbs Banksia Scrub, which is a critically endangered ecological community. The Sanctuary, located on the doorstep of Sydney Harbour, is home to the largest remaining patch of this important scrubland, of which only 3% remains! Each year, the reintroduced possum population has increased in size, ensuring that these pocket-sized pollinators will continue their important ecological roles.
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