The Christmas Island pipistrelle has less than 6 months to live unless taken into captivity immediately to set up an emergency captive breeding programme for future re-release.
This unique bat is one of the world’s smallest mammals, with 3cm wings and weighing just 3 grams (0.1 ounce). Christmas Island is said to be of ‘immense scientific value’ due to its high proportion of endemic species, its flora and fauna having been isolated for many millennia. All five of its native mammals are endemic to the island, but three have already been lost to extinction following human settlement and the introduction of alien species. The other two, the Christmas Island flying-fox Pteropus melanotus natalis and the Christmas Island pipistrelle Pipistrellus murrayi, have both suffered severe declines. The Australian Bat Society has issued the stark warning above in the hope that the government will fund their proposed emergency rescue programme, which needs to go ahead within the next three months in order to save the species.
The Christmas Island pipistrelle is the island’s only insectivorous bat, so its loss is likely to impact this delicate and ancient ecosystem. Common across the island as recently as the 1980s, it took a 99% nose dive in numbers between 1994 and 2006. There may now only be twenty individuals left, and the only known remaining communal roost has just four individuals. Its habitat and food source remain abundant, and no evidence of disease has been found so far. The most likely cause of this decline is thought to be predation by introduced non-native species such as the common wolf snake, feral cat, giant centipede and black rat, and the risk of there being so few individuals left that it is impossible to catch them for captive breeding is growing by the day.
Recent genetic research on museum specimens of the island’s two extinct native rodents, Maclear’s rat Rattus macleari and the bulldog rat Rattus nativitatis, found that they had been infected by a disease introduced to the island with the arrival of black rats from European ships. The Christmas Island shrew Crocidura attenuata trichura was ‘extremely common all over the island’ in 1900, but its distinctive shrieking call had almost vanished by 1909, and in the past half-century it has only been reported twice. Australian mammalogists consider that the invasion of the yellow crazy ant is responsible for ‘driving the last ecological nails into this shrew’s very small coffin’.
-The Australian Bat Society’s report can be viewed here
-The scientific paper documenting the extinction of the Christmas Island rat Rattus macleari can be viewed here
-NASA satellite imagery can be viewed at the Visible Earth website