The red crab population on Christmas Island has drastically increased due to additional pest control measures to protect the crabs from invasive crazy ants.
Christmas Island National Park Invasive species program coordinator Tanya Detto says a recent survey estimates the current red crab population at over 190 million, which indicates an almost four fold increase in population average over the past 20 years.
Scientists from Latrobe University have been experimenting with methods of controlling the large numbers of crazy ants, which have been known to kill red crabs by spitting acid on them, and Dr Detto believes these pest control methods have been instrumental in restoring red crab numbers.