In the general silence, the Christmas Island shrew (Crocidura trichura) disappeared forever. The IUCN, the International Union for Conservation of Nature, has made its extinction official in 2025, marking a new sad record for Australia. This small mammal, the only representative of its species on the continent, was just a few centimeters long and weighed less than five grams, but it represented an important piece of the local ecosystem.
Crocidura trichura lived only on Christmas Island, an Australian territory located over 1,500 kilometers from the mainland and closer to Indonesia than to Canberra. It was an endemic species, meaning it was present exclusively in that area, and since its discovery it had shown shy and difficult to observe behaviour. There are very few photographs available and the last sightings date back to the 1980s. Since then, no signal.
An announced decline
Experts believe the causes of the disappearance are multiple: habitat destruction, predation by cats and rats introduced by settlers, and even the spread of the yellow crazy ant, one of the most invasive species on the planet. These factors have progressively reduced the population of the small mammal, until it finally disappeared. The last known specimen was observed in 1985, and since then there has been no trace, not even in checks on predatory animals on the island.
An ecosystem in crisis
With this new extinction, Australia reaches the record figure of 39 mammal species that have disappeared since 1788, the year of the arrival of the first European settlers. This is a loss equal to 10% of the continent’s native fauna, a figure that makes the country one of the most affected in the world by the decline of biodiversity.
The disappearance of the Christmas Island shrew is just the latest sign of a larger problem: the fragility of island ecosystems and the difficulty of protecting them from invasive species and environmental change. Today, while scientists urge us not to lose hope of finding some specimens, the story of little Crocidura becomes the symbol of an ecological battle that humanity cannot afford to lose.
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