The International Union for the Conservation of Nature (IUCN) has declared the Christmas Island shrew extinct in its latest Red List update. This marks the loss of Australia’s only native shrew species, bringing the total number of Australian mammal extinctions since 1788 to 39—more than any other country.
The Christmas Island shrew, a small insect-eating mammal, likely arrived on the remote Australian territory thousands of years ago by rafting on vegetation from Indonesia. It thrived until European settlement in the 1890s, when black rats were accidentally introduced, carrying trypanosome parasites that devastated native wildlife.
By 1908, the shrew was thought extinct, but two individuals were found in the 1950s during mining clearance. In 1984, a female was captured and kept in captivity, followed by a male in 1985. However, the pair were not bred, and no shrews have been seen since. The IUCN now lists the species as extinct, highlighting the vulnerability of island ecosystems to invasive species and disease.
