More than beauty
In south-west Western Australia, an incredible diversity of plants sustains an incredible diversity of pollinators. So what happens when both are under threat?
Sweet is the life of the Honey Possum. It can drink 7ml of nectar a day, which would be like a human drinking 50 litres of soft drink!
Also known by its Aboriginal (Noongar) name Noolbenger (ngool-boon-goor), this creature is tiny. It weighs just 7 to 10 grams and has a tail 88mm to 100mm – longer than its head and body combined!
Like a Pygmy Possum, the Honey Possum’s tail is prehensile – it can grasp branches, enabling the animal to move nimbly through vegetation. A dark brown stripe runs across the noolbenger’s back, marking its grey-brown fur coat.
What's in a name?
Honey Possums are famous for their long snouts – the genus name, rostratus, means ‘beaked’ in Latin.
But their common name is less informative. Honey Possums are only distantly related to possums and don’t actually eat honey!
While these animals are expert climbers, and are mostly arboreal (tree-dwelling), they’re also fast runners.
Like nectar-eating birds they have bristles on their tongue tip, used to collect nectar from native flowers. The upper surface of the tongue is covered by brush-like bristles that collect pollen. At 1.8cm, a Honey Possum’s tongue is almost one-quarter of its head and body length.
Like a Hummingbird, the Honey Possum’s tongue moves rapidly in and out of the mouth (at about three times a second).
Where do Honey Possums live?
The Honey Possum is endemic to the south-west of Western Australia. It’s a totem animal for some of the Noongar Traditional Custodians of this region.
Honey Possums live in Banksia woodlands, sandplain heathlands, shrublands and low open woodlands. The species is now extinct in most of the Central Wheatbelt, where much of this vegetation has been cleared.
Honey Possums are most abundant where vegetation hasn’t been burnt for 22 to 26 years: the population is double in these areas, compared to recently burnt sites.
Ultimately, their distribution is dependent on the number (species richness) of different nectar-producing plants, and their time of flowering as they need flowers for their food supply all year round.
Internationally the species is considered of Least Concern to extinction by the International Union for Conservation of Nature (IUCN) Red List of Threatened Species. However, it’s protected fauna in Western Australia.
Honey Possum behaviour
Honey Possums are mainly nocturnal but on cloudy days they can be seen visiting flowers from dawn until dusk. They feed on banksias, bottlebrushes, heath, grass trees and kangaroo paws.
As they have such a high metabolic rate, they need a year-round, continuous supply of nectar to survive. And plants need them: Honey Possums pollinate many plant species by transferring pollen collected on their head and body between flowers.
– Angela Sanders, Ecologist“The evolutionary trail of this animal is quite incredible. South-west Western Australia is the only place in the world where they could have evolved. That’s because it’s the only place where pollen and nectar has been readily available for all 12 months of the year over such a long period of time.”
Male Honey Possums are smaller than females, but have extremely large testes (up to 4.2% of their body weight) and the largest sperm of any mammal in the world!
Females give birth to two to three young – joeys – at any time of year, whenever food is abundant. Being a marsupial, the mother raises the tiny new-borns in her pouch, suckling them until they’re about three months old.
In cold or wet weather they can enter a state of torpor, conserving energy by lowering their metabolic rate and internal temperature. They sometimes huddle together in a cluster to keep warm. In the wild they have quite a short life-span, living 1 to 3 years.
Threats to Honey Possums
Habitat loss is the biggest threat to the survival of Honey Possums. They rely on a rich diversity of flowering plants so that at any time of year at least one species can supply nectar.
Unlike nectar-eating birds and bats, they can’t fly to different areas to source flowers. Females with joeys are recorded moving less than 10m over several months!
Even brief food shortages can drive local populations extinct. Threats include inappropriate fire regimes; habitat loss from the water mould Phytophthora cinnamomi; and predation by cats and foxes.
It’s also predicted that climate change will result in less rain and increased wildfires in their habitat.
What’s Bush Heritage doing?
Honey Possums live on several of our Western Australian reserves and partnership properties: Beringa, Chereninup, Chingarrup, Monjebup and Yarraweyah.
We’re protecting the habitat of these noolbengers by removing stock, controlling feral herbivores (rabbits) and revegetating cleared land with proteaceous plant species, which is their preferred food.
Image Information
Honey Possum feeding on Banksia flower. Photo by Barry Baker.
