Folks living on Christmas Island, an Australian territory in the Indian Ocean, were greeted with a familiar but bizarre sight this week: thousands of bright red crabs scuttling en masse down roads, across yards, and over special bridges set up for them to cross busy streets.
These crabs (species name Gecarcoidea natalis) live only on Christmas Island, which has an estimated 120 million of them. (That gives the crabs a more than 91,000-to-1 ratio with the island’s human inhabitants.) This week, they’re making their annual journey to the coastline for the start of the mating season.
“This year’s migration has just been absolutely epic,” Christmas Island National Park natural resource manager Brendan Tiernan told Reuters. “The roads have been a seething mass of red crabs. It’s caused traffic jams on this small island and people having to get out of their cars and rake them out the way.”