Why millions of red crabs are causing chaos on Christmas Island in Australia

Millions of red crabs have appeared on roads, bridges, and even office blocks. Credit: Parks Australia/Chris Bray

Millions of red crabs are causing disruption on Christmas Island in Australia.

The crustacean invasion has led to road closures and traffic delays as wildlife teams clear them out the way.

The crabs are making their yearly migration from the jungle to the beach on the island, 220 miles south of Indonesia.

The red crawlers have appeared "everywhere" - including doorways, bridges, and even office blocks, according to Parks Australia.

Parks Australia - the organisation that maintains the country's national parks and wildlife - has sent staff to clear crabs off roads and manage traffic.

The crustaceans have appeared in doorways, on their march from jungle to beach. Credit: Parks Australia
The crabs have their own special bridge to keep them safe from traffic. Credit: Parks Australia/Chris Bray
Credit: Parks Australia/Chris Bray
Credit: Parks Australia/Chris Bray

The first rainfall of the wet season, which falls in October or early November on the island, usually marks the start of the crabs' migration. Heavy rain at the start of November prompted the male crabs to leave their homes and march towards the beach, where they meet females along the route.

Australia's national parks and wildlife authority has sent teams out to sweep the red crabs off the roads. Credit: Parks Australia

A female crab releases about 100,000 eggs into the Indian Ocean over the course of about five or six nights during the migration. A month after this, the baby crabs that hatch from these eggs return to shore and head towards Christmas Island's jungle, before the process repeats itself.