Red crab migration

Every year, as the monsoon rains arrive, the red crabs of Christmas Island (Australia, Indian Ocean) come above ground and leave their forest refuge for a dangerous trip to the coast where they need to breed in the sea. This is one of earth's most spectacular wildlife migrations.
More than one hundred million crabs move almost together in a dash to the coast. A weeklong trip for most, during which instinct and survival of the specie is more important than survival of the individual. Crabs loose their fear, and cross all obstacles. Especially those created by man: roads, walls, factories, and mines…

Parks and Wildlife have close roads where up to a million used to be killed by traffic and created passages to avoid further damages. But this is not the only problem as an African ant introduced with plant material is a more dangerous threat killing very young crabs, and where ants live the whole area is devoid of the once over abundant crabs. Ants are under control but nowhere near eradication despite efforts.

The unique environment of Christmas island harbors one the worlds richest diversity of land crabs (at least 7 species) including the giant robber now threatened over most of it’s range. A vegetarian that climbs trees for nuts, but eats also rotten meat and has no qualms about hunting fellow red crabs and feed on them during the migration. Then a massive, but slow, predator!