- Who
- Christmas Island red crabs
- Where
- Weihnachtsinsel ()
- When
- 2015
At the last population count in 2015, a total of 38 million Christmas Island red crabs (Gecarcoidea natalis) lived on the 135‑km² (52-sq-mi) Christmas Island and nearby Cocos (Keeling) Islands in the Indian Ocean – around 280,000 crabs per km² (730,000 per sq mi).
Numbers of the Christmas Island red crabs have plummeted since the invasion of the yellow crazy ant (Anoplolepis gracilipes) to the island. In 2017, researchers tried to arrest the decline by introducing a “biocontrol agent”: Malaysian wasps, which eat the crazy ants’ primary food source.
Dr Tanya Detto of Christmas Island National Park estimates that numbers may have recovered to around 40 million as of February 2020.
