By Mitch Greenwood
As the last light of day diminishes, Richard Kingsford sits alongside a river-bank, waiting. The hum of mosquitoes and other insects is his constant companion.
Then, what he has been waiting for: a visitor. The tell-tale circle of ripple-waves heralds its arrival. It’s a platypus – often described as the world’s most peculiar animal. Silent, almost like a shadow through the water, it makes its way downstream.
But there’s a key question in the mind of Kingsford, Professor of Environmental Science at the University of New South Wales: “Is this the same platypus I have seen many times before … or is it a new arrival?” The answer is important, because the issue of whether platypus numbers are steady, or in sharp decline, is being hotly debated in research and community groups.
As Professor Kingsford says: “They come out at night and are very difficult to detect.” In other words, trying to work out whether Australia’s platypus population is threatened, or not, is difficult to work out.
Source: Rodney Morse, @tasmanianpics
The National Geographic Australia says the platypus is one of the most unusual creatures in the animal kingdom. It says: “When first discovered, European naturalists and scientists believed that the animal was an elaborate hoax. They thought that a trickster had sewn many different animals together as it had, a paddle-shaped tail like a beaver; a sleek, furry body like an otter; and a flat bill and webbed feet like a duck.”
The platypus is unique to Australia and is so important that since 1966 has been celebrated as the design on the 20-cent coin. But while there have been more than 2 billion platypus-design coins minted since 1966, there is increasing evidence the number of real, living platypus has become close to threatened.
Dr Melody Serena, Director of Research at the Australian Platypus Conservancy is cautious about platypus numbers but says the species can be considered “near-threatened”, claiming that community populations can decline by up to 30% over three generations.
“It does not mean that it’s going down 30% every three generations, it means it has the potential to do that, and it doesn’t mean that the populations can’t go up again,” Dr Serena says.
Professor Kingsford says the problem of understanding whether the platypus is threatened or not comes down to the counting of the population.
He says: “No one has any idea how many platypus there are in Australia, but it would be in the thousands, perhaps tens of thousands.”
Taronga Zoo conducts significant research into platypus and is one of few organisations in the world to have successfully bred platypus in captivity. It says: “The predominant threat to platypus on the mainland is reduction in stream and river flows due to extraction of water for agricultural, domestic, and industrial supplies.
“Deteriorating water quality also adversely affects its habitat, particularly from household chemicals, pesticides and fertilisers that enter a waterway through storm run-off after being poured onto the ground or into a gutter.”
“Accidental drowning in nets and traps set for fish and crustaceans has the potential to impact platypus distribution and abundance in all parts of its range, especially in small streams where populations may be critically small. Feral cats, foxes, dogs and dingoes also kill platypus that move on land or in shallow waters.”
But Dr Serena says: “The threat categories are not… ‘hand-wavy’, they are based on specific criteria, as you’d expect.” In other words, the science has to be precise.
One of the key threats to platypus is human intervention. Hundreds of platypus are believed to drown in fishing nets each year across Australia, platypus ecologist Josh Griffiths told ABCNews.
In response, major retailers including K-Mart, Big W and Anglers Warehouse have discontinued stocking yabby nets.
The urgency of gathering credible information about platypus numbers is important from a scientific and ecological point of view.
Professor Kingsford says: “They are iconic, one of only two egg laying mammals in the world. They are clearly one of the most important animals in Australia and the world – they are unique.”
But apart from their uniqueness, they have properties that may help medical research, specifically ovarian cancer.
Australian Geographic has reported: “DNA mapping of the platypus has uncovered an interesting relationship between their sex chromosomes and DNA sequences found in human ovarian cancer.”
Source: Discovery Channel
The important thing, for now, is to discover whether very Australian creature is threatened. And that’s why researchers including Professor Kingsford sit on the banks of rivers and creeks, peering into the dark, hoping to catch a glimpse of one of the world’s most unusual creatures.
As he says: “I suspect the rate of decline may qualify them to be listed at a higher level of risk of extinction.”