Christmas Island, a secluded piece of paradise nestled in the Indian Ocean near Australia, is home to an astonishing population of around 55 million red crabs, scientifically termed Gecarcoidea Natalis. Each year, from October to December, which marks the beginning of the rainy season, these brilliant red crabs undertake an extraordinary trek from the forest to the shores to reproduce.
Timing of the Annual Trek
Aligned with the specific phase of the moon, the female red crabs release their eggs into the ocean usually before dawn during the spring tide periods at the lunar last quarter. This mass migration is carefully timed: the crabs embark on their lengthy journey to ensure mating, incubation of their eggs and reaching the ocean for spawning synchronously.
This year’s predicted spawning windows fall within the periods of November 22-24 and December 21-23. Red crabs commence their voyage five to six weeks preceding these intervals, navigating treacherous cliffs, dense forests, and even man-made roads to reach their destination.
Life Cycle of the Red Crab Brood
Upon arriving at the coast, red crabs refresh themselves in the salty ocean to rejuvenate and replenish essential minerals. Subsequently, males excavate burrows in the sand for courting and mating. Post-mating, males begin the return journey inland.
Meanwhile, the females linger inside their shelters, nurturing the developing eggs for about a fortnight before releasing them into the ocean, marking the beginning of a new generation. These eggs swiftly transform into larvae, and then into diminutive baby crabs, each with a fragile five-millimeter shell. These young crabs promptly initiate their own pilgrimage back to the forested home of their ancestry. Within four to five years, they will have matured into adult crabs, ready to participate in the cycle of reproduction.
Conservation Efforts by Christmas Island Locals
Christmas Island’s residents proactively engage in protective measures to safeguard the migrating crabs. They have crafted bridges and subterranean passageways specifically designed to prevent road casualties. The island authorities temporarily shut down certain roads, rerouting traffic during the prime period of crab movement, ensuring a safe passage for the crimson wave of crustaceans.
A Glimpse into Christmas Island
Christmas Island, an offshore territory under Australian jurisdiction, is situated some 220 miles away from the Indonesian islands of Sumatra and Java and lies about 990 miles northwest of the Australian mainland. Spanning an area of 52 square miles, this island is a unique ecological haven.
Fascinating Tidbits about the Island’s Red Crabs
- Historically, the Christmas Island red crab population peaked at a staggering 100 million. However, the inadvertent introduction of Yellow Crazy ants has resulted in the demise of 20-30 million red crabs in recent times.
- Humans unwittingly introduced these invasive ants around the year 1915.
Image Source: MKInayem / Shutterstock
