Platypus in Hornsby Shire

• Platypus brochure (PDF 1.4MB)
• Sampling site location map (PDF 4.5MB)
• Mayors letter to catchment residents – Platypus eDNA project (PDF 82kb)

The plural of "platypus" has long been established in the English-speaking world as "platypuses." This is due to the Greek root of the name ("flat-foot"). The actual Greek plural for "platypus" is "platypodes," but this isn't used in English. "Platypuses" is the accepted plural form because it aligns with the regular pluralization rules for words of Greek origin and is endorsed by authoritative language sources such as the Oxford English Dictionary and Merriam-Webster.

As for “platypi”? Well, English is an evolving language, and common usage sometimes dictates a word's acceptance. So, using "platypi" may be a fun and quirky informal term, but strictly speaking, it's not considered correct by most authorities on English usage, including major dictionaries and linguistic guides.

The platypus (Ornithorhynchus anatinus) – or duck-billed platypus - is:

• a unique, venomous, semi-aquatic mammal that lays eggs and uses its super sensory bill – like an electric sixth sense - to hunt prey in murky water
• one of very few venomous mammals in the world. The spur on the male’s hind foot is connected to a venom-secreting gland and is likely used in aggressive encounters between rival males
• not considered endangered but the International Union for Conservation of Nature has upgraded their status to 'Near Threatened'
• protected by legislation in all of Australia's eastern states
• threatened with local extinction in areas where they once thrived due to bush fires, drought, deforestation, predation, and pollution of waterways
• the animal emblem of NSW and well-known animal symbol of Australia
• famous as the mascot for the Sydney 2000 Olympics
• along with the echidna, the only mammals that lay eggs - they also feature on our 5 cent and 20 cent coins
• The name Platypus comes from the Greek word for ‘flat-footed’ – they're very awkward on land, walking on their knuckles to protect the webbing of their feet
• Baby platypuses are called “platypubs” (and baby echidnas are called “puggles”).

Platypuses occur in freshwater systems from tropical rainforest lowlands and plateaus of far northern Queensland to cold, high altitudes of Tasmania and the Australian Alps. Elusive by nature, there’s a lack of reliable data about where and in what numbers they occur. Their distribution is unpredictable, as they appear to be absent from some relatively healthy rivers yet have been found in others that are quite degraded.

Platypuses make their home in and near freshwater creeks, slow-moving rivers, lakes joined by rivers, and built water storages such as farm dams.

They build a simple burrow in a riverbank, just above water level and often among a tangle of tree roots.

Hornsby Shire contains many areas that appear to be suitable habit for platypus including the upper reaches of Berowra Creek and Cowan Creek catchments, particularly those areas in rural or undisturbed bushland catchments.

• The first ever record of a platypus sighting by a European colonist was near the Hawkesbury River in 1797.
• Platypus were also observed in Epping bushland in the early 1900’s.
• In 1976, one was observed at Milson Island on the Hawkesbury River just north of Muogamarra Nature Reserve.
• In 1977, one was observed near Kimmerikong Creek west of Cowan within Muogamarra Nature Reserve itself.
• In 1982, a platypus was observed on the north side of the Hawkesbury River in Dharug National Park.
• In 1983, there were two sightings within Ku-ring-gai Chase National Park along Cockle Creek, just South of Bobbin Head; and near the entrance to Cowan Creek on the northern bank.

The platypus usually lives alone, and numbers are most often limited by the availability of food, mainly in the form of tadpoles,water bugs, shrimp, and swimming beetles. When not foraging they spend their time in their burrows which they build in the banks of creeks, rivers, or ponds.

They feed in both slow-moving and rapid parts of creeks and rivers but seem to prefer areas with cobbles and gravel. At times, they use rocky crevices and stream debris as shelters, or they burrow under the roots of vegetation near the waterway. Hence, the ideal habitat for the species includes a river or a creek with earth banks and native vegetation that provides shading of the waterway and cover near the bank.

People hunted the platypus for their fur in the early 1900s, but they're now protected. Platypus populations are believed to have declined or disappeared in many catchments, particularly in urban and agricultural landscapes. Given their dependence on freshwater systems, destruction of creek bank plants, siltation and other waterway pollution are major threats. Water extraction, dams and diversions to water flow have a big impact. Water quality and in-stream habitat (such as submerged roots, branches, and logs) are critical, so degradation of these elements is a threat. Run-off from agriculture (sediments and nutrient load) can degrade platypus habitat. If you catch yabbies, you should know that Opera house-style yabby traps are illegal and have caused many drownings of platypus, native water rat (rakali), and turtles. Please do not use them!

Platypus can be killed by being sucked into the unguarded inlets of irrigation pumps or mini-hydroelectric generators. Water extraction or removal can also contribute to reduced water flow in creeklines and cause a reduction in the overall amount of platypus habitat.

Natural predators of the platypus include snakes, water rats, goannas, hawks, owls, and eagles, yet these are unlikely to have affected overall platypus numbers. Up until the early twentieth century, they were widely killed by humans for their fur, and introduced predators such as foxes, dogs and cats are presumed to have had a major impact on populations.

Platypuses are also vulnerable to the effects of pollution and declining water quality. The misuse of chemicals (such as pesticides, herbicides, surfactants, and fertilizers) near waterways can disrupt the aquatic food chain, greatly reducing the platypus food supply. For the platypus to stay warm while in the water, its fur must remain completely clean and waterproof, and not be fouled by oil or other pollutants. Furthermore, they are not adept at removing objects caught around the head or body and can die after becoming ensnared in litter such as loops of nylon fishing line or even hair tie elastics.

Platypus and their food species struggle to survive in areas where native vegetation has been cleared from creeks and riverbanks. Furthermore, due to Hornsby’s ridge top style development, and past poor building site sediment control practices, many of the deeper ponds along our local creeklines have been filled with sediment from urban run-off. The expansive hard surfaces and stormwater systems of our urban areas have created fast-flowing, high-energy surges whenever it rains. Such conditions may not be ideal habitat for platypus nor their prey.

As part of a worrying trend, the platypus has been in decline across much of its traditional range due to river mismanagement, habitat destruction, predation by invasive species, and an increased frequency and severity of droughts and fires due to climate change. The future of this extraordinary monotreme lies in the balance. Platypus are facing a silent extinction and it is vitally important for all of us to take action to protect them and their habitat

Please don't disturb platypus if they live in creeklines on your property or in your local catchment.

You can help the platypus living in your area by planting and maintaining locally native riparian-friendly plants along waterways. If you do this, you will protect the creek banks and provide areas for the platypus to live.

To prevent platypus and other aquatic wildlife from drowning or otherwise dying after being sucked into water extraction pumps or water-powered generators, a mesh cover or equivalent barrier should be fitted at an appropriate distance around all intake points and checked regularly.

Spread the word among friends and acquaintances that Opera House-style yabby traps and homemade equivalents are responsible for drowning many platypuses, Australian water rats (Aboriginal name, Rakali) and freshwater turtles each year. From 30 April 2021 yabby traps (“opera house”) are illegal and no longer permitted in NSW waters.

Don't let your dogs and cats wander unsupervised at night - this will help safeguard the welfare of your pets as well as wildlife. Obey local laws which prohibit the presence of unleashed pets in Wildlife Protection Areas. Even during the day, uncontrolled dogs and cats can disrupt the natural behaviour of platypus and other native species occupying such habitats.

And remember – whatever goes down the drains of our stormwater system ends up in the local creek – where the platypus are trying to survive.

Platypus in the Hills Shire – CHEN Inc

• Cattai Hills Environment Network (CHEN Inc.)

General Platypus Information

• Australian Platypus Conservancy
• Australian Museum information
• Taronga Conversation Society
• National Parks and Wildlife Service
• Bush Heritage Australia
• Queensland Department of Environment and Science

Yabby Trap Threat

• ABC News: Platypuses found dead on NSW mid north coast prompt calls for more action on illegal yabby traps

Platypus eDNA Research

• Platypus eDNA - Land for Wildlife
• Environmental DNA (eDNA) – Australian Platypus Conservancy

Melbourne Water and Platypus

• Case Study Melbourne Water Waterwatch Program
• Platypus census | Melbourne Water
• Urban platypuses: threats and challenges | Melbourne Water
• Citizen science eDNA monitoring of platypuses in Monbulk Creek & Werribee River | Melbourne Water
• Platypus eDNA collection - Werribee River | Melbourne Water

General Platypus Video’s

• You've probably never see one in the wild, but there's platypuses in Sydney's suburbs | ABC News - YouTube
• Meet the Tasmanian 'platypus whisperer' whose citizen science is surprising the experts | ABC News - YouTube
• Platypus populations could disappear 'without ever returning', new research finds | ABC News - YouTube
• Melbourne Water Platypus Program - YouTube