Because a platypus mainly feeds on bottom-dwelling insects, much of its time is spent investigating the channel bed where litter tends to accumulate. A platypus also finds it very difficult to remove loops or rings that encircle its neck or body: its front feet end in broad flaps of skin that make great paddles but cannot grip or grab. The back feet are more dexterous, but can’t remove a loop except by trying to pull it back farther along the body.
An encircling loop or ring therefore tends to remain in place until the loop breaks or the platypus dies – often due to horrific injuries that develop as the item gradually cuts through the skin and underlying tissue.
Virtually any rigid or flexible loop – particularly those with a diameter of 4 to 8 centimetres – can cause life-threatening platypus injuries (Serena and Williams 1998, 2022). For example, all of the following items have been recovered from a platypus (some alive, others dead): loops of fishing line, plastic cable-ties, wide and narrow rubber bands, engine gaskets, a bicycle head lamp rim, knotted loops of twine, a rubber bottling jar seal, a hospital identification wrist band, a short length of PVC pipe, tamper-proof food jar rings, plastic bracelets (as shown above) and elastic hair-ties (as shown at left) (Serena and Williams 1998, 2010, 2022).
An analysis of platypus mortalities from 1989 to 2009 found that litter (including fishing line) contributed to 12.5% of platypus deaths in Victoria caused by factors other than illegal nets and enclosed yabby traps (Serena and Williams 2010). Similarly, platypus live-trapping surveys conducted in Victorian waters from 1989 to 2019 found that around 4% of individuals across the greater Melbourne area and 0.5% of those living in regional areas are on average entangled in rubbish at any given point in time, with this being true for 15% of individuals living in the Werribee River (Serena and Williams 2022).
Pollutant traps can be fitted to collect rubbish from stormwater drains to reduce litter in natural channels. However, pollutant traps are generally not designed to intercept the small items that typically end up being looped around a platypus’s neck or chest. In addition, many dangerous items – such as discarded fishing line or hair-ties that are dropped while swimming – can enter a creek or river directly, without ever having travelled down a drain. The key to reducing litter-related deaths is therefore changing the way that humans deal with litter on a day-to-day basis (Serena and Williams 2022).
You can reduce the risk that a platypus dies a slow and horrible death due to rubbish entanglement by adopting a few simple habits:
- Pick up litter – particularly anything that looks like it could eventually get caught around a platypus’s bill, neck or body – whether or not it’s found near water.
- Spread the word, particularly to children, that carelessly dropped personal items such as plastic bracelets or elastic hair-ties can have lethal consequences for wildlife. Items dropped on sidewalks or in playgrounds may still end up in platypus habitats after being carried long distances through stormwater drains.
- Make it your habit to cut through ALL metal or plastic rings or loops of any size before disposing of them – just to be on the safe side.
Photos courtesy of J. Shaw (middle), APC (top and bottom)
LITERATURE CITED
Serena M and Williams GA (1998) Rubber and plastic rubbish: a summary of the hazard posed to platypus Ornithorhynchus anatinus in suburban habitats. The Victorian Naturalist 115, 47-49.
Serena M and Williams G (2010) Factors contributing to platypus mortality in Victoria. The Victorian Naturalist 127, 178-183.
Serena M and Williams GA (2022) Factors affecting the frequency and outcome of platypus entanglement by human rubbish. Australian Mammalogy 44, 81-86.