Once abundant on its island home, numbers of this neglected bat plummeted in the 1990s.

Thumbnail-sized – This micro-bat was truly tiny, weighing in at just 3-4g (0.11-0.14oz), with a forearm length of around 3cm (1.2in).

Big appetite – It might have been small, but a fast metabolism meant the Christmas Island pipistrelle could eat up to its entire body weight in insects in a single night

Blind as a… – Like most bats, it relied completely on extremely sensitive hearing and its supersonic vocalisations, which it used to pinpoint prey like a submarine sonar.

Like its common British cousin, the Christmas Island pipistrelle was a small, nocturnal bat that could easily have fit into the palm of your hand. It was native to the Australian territory of Christmas Island, which is located in the Indian Ocean, just off the coast of the Indonesian island of Java. Up until around 30 years ago, the population of this tiny bat was relatively healthy.

Females of the species would gather in huge colonies that numbered in the dozens, while males preferred a more solitary existence. Their favourite roosting sites would be in trees, in the cavity formed by exfoliating bark or underneath the withering fronds of dead palm trees, which should give you an idea of just how small these creatures were.

Their habitat was tropical, with dense rainforest along the plateau of the island, high humidity and temperatures that varied little from season to season. Along the edge of the canopy, this insectivore would have found no shortage of its favourite foods, moths and beetles.

The occasional cyclone would have posed some threat to the Christmas Island pipistrelle, but having survived these storms for hundreds of thousands of years, it’s unlikely that its sudden decline in numbers can be attributed to one or even several extreme weather events.

In the early 90s, scientists began using bat detectors that recorded the Christmas Island pipistrelle’s supersonic calls. Over successive years, they reported a 33 per cent decline in the bat’s activity that continued to a critical level by 2009.

The reason why the Christmas Island pipistrelle’s population took a sudden nosedive is still not clear – it could have been down to pesticides or attacks from an invasive species, such as the yellow crazy ant. It was the first Australian mammal to go extinct in 60 years.

Last seen…

Date: 26 August 2009

Location: Western Christmas Island

By January 2009, at least 80 per cent of the Christmas Island pipistrelle’s population had disappeared and they were now isolated to just a single, small colony on the west side of the island. Surveys showed that the species would be extinct before the year was out, unless the Australian government intervened with suitable funding.

But despite a meeting with the environment minister where the Australian Mammal Society emphasised the urgency of the situation, the cogs of bureaucracy were too slow to turn. By late August that year, just a single, plaintive echolocation was recorded above the canopy of a known roosting site, and it has been silent ever since that night.