It's official: Australia's only shrew is no more.
Latest publication of the International Union for Conservation of Nature Red listThe world's most comprehensive global extinction risk register has announced that the Christmas Island shrew has gone extinct.
The news may not seem that important. After all, most Australians know nothing about shrews and are unaware that the species is part of our native fauna.
But the shrew's extinction brings the number of Australian mammals extinct since 1788 to 39 types. This is much more than for any other country. These losses represent about 10% of all Australian terrestrial mammal species before colonization. This is a sad example of the destruction of an outstanding heritage.
So what are shrews?
Shrews are small, long-nosed insectivorous mammals, many species of which are widespread in Asia, Africa, Europe and the Americas. On mainland Australia, a similar role is played by unrelated small marsupials such as dunnarts, antechinuses, planigals and nyngauis, which in themselves have little importance in our national consciousness.
Many people only know about shrews thanks to Shakespeare. Combining misogyny and zoophobia (intense fear of animals), he used the name this harmless animal to describe a shrill, constantly complaining and annoying caricature of women. The offensive term has stuck for centuries, draining sympathy and interest in the animal.
History of the Australian Shrew
It must have been a harrowing journey. Tens of thousands of years ago, a small family of shrews (or a pregnant female) floated on floating vegetation from the islands of what is now Indonesia. By chance, they landed on the uninhabited Christmas Island, which is now Australian territory, about 1,500 km west of the mainland. These lucky or foolhardy pioneers gave rise to Australia's only species of shrew.
For many years the shrew has flourished on Christmas Island. When European naturalists first visited Christmas Island in the 1890s, during its settlement, they noticed:
This animal is extremely common throughout the island, and at night its piercing squeal, similar to the cry of a bat, is heard from all sides.
After this, changes happened quickly. In 1900 black rats were accidentally introducedstowaways on hay bales. To make matters worse, these rats were infected with trypanosomes, cell parasites. These trypanosomes quickly spread to the island's two native rat species (and presumably the shrew).
Christmas Island's long isolation has consumed the native mammals, leaving them resistant to new diseases. Within a year, the island's residents began seeing scores of dying rats stumbling across the forest floor.
By the time naturalists next visited the island in 1908Two species of native rats and the Christmas Island shrew were thought to be extinct. Subsequently, many other endemic animals were also lost or severely declined due to the introduction of cats and invasive species of ants, snails, plants, giant centipedes, birds and snakes.
This is a sample that has happened repeatedly on the islands of the world. The introduction of plants and animals has disrupted island ecosystems and, as a consequence, endemic island species represent a disproportionate number of the world's endangered species.
Challenging extinction?
But there was an obstinate vein. The two survivors, who had not been seen for more than 50 years, were captured in the 1950s as bulldozers cleared an area of rainforest for mining. The shrews were released, and the discovery was reported only many years later.
Then nothing for another 30 years. In December 1984, biologists Hugh Yorkston and Geoff Tranter were clearing a path in the rainforest when they came across a live female shrew in a thicket of fern that had fallen from a bird's nest. They kept the shrew in a terrarium for 12-18 months, diligently catching grasshoppers to feed her.
At the time, they did not consider this the last opportunity to preserve the species through a captive breeding program. When, just a few months later, in March 1985, by an incredible stroke of luck, a male shrew was found alive, he was placed in a separate terrarium. The female was docile, but the male was aggressive. It also looked unhealthy.
Whatever the reason, there was no acquaintance, no consummation, no young shrews. The male died approximately three weeks after capture, leaving the female alone.
There are no shrews left
There have been no recorded sightings since 1984. This means there are only four shrews recorded on Christmas Island. more than 120 years.
Almost no information about the biology of this species has been published, except for a single sentence written by naturalist Charles Andrews. in 1900:
It lives in burrows in rocks and tree roots and appears to feed mainly on beetles.
There are few pictures. However, hints of the nature of the last known shrew can be seen in a wonderful sketch by park ranger, naturalist and artist Max Orchard.
In the nearly 40 years since the death of the last famous person, two recovery plans documents were drawn up outlining the actions necessary to preserve the species. There were targeted searches. But not a single shrew benefited from these plans.
The clearest evidence of their extinction is the absence of shrews from the stomach contents of hundreds of wild cats killed over the past few decades.
Although the shrew clearly survived into the 1980s, another threat emerged this decade: the Asian wolfsnake. This snake quickly spread across the island, most likely leading to the extinction of the island's endemic bat species. Christmas Island pipistrellein 2009 and in most Endemic lizards. The snake's arrival also likely sounded the death knell for any remaining shrews.
We must do more to prevent extinction
Extinction can be difficult to prove, especially for a species as mysterious as the shrew. There is a danger of classifying a species as extinct if it still exists. This misclassification is called “Romeo's mistake“, where formally declaring a species extinct may result in the loss of funding or protection and therefore increase the likelihood of actual extinction.
In 2022, the Australian government, through then Environment Minister Tanya Plibersek, promised to prevent any more extinctions. Although official recognition of the shrew's extinction occurred after this promise, the last shrew had probably died a decade or two earlier.
The shrew's death is a reminder of the enormity of the challenge of preventing further extinctions, the different ways in which these losses can occur, the need to seize opportunities to protect rare species, and the importance of national and political obligation to prevent disappearance.
I hope the Christmas Island shrew is not extinct; after all, he defied previous calls for his demise. Perhaps there lives a small secret family of shrews somewhere, elusive survivors, confident in their existence and waiting to prove the pessimists wrong.
Hugh Yorkston, Geoff Tranter and Paul Meek contributed to this article.
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John Woinarski is Professor of Conservation Biology at Charles Darwin University.
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This article was originally published in Talk
