Christmas Island is known as "the Galapagos of the Indian Ocean," a reference to its small size, remote location and array of native wildlife. One of its most famous residents is the Christmas Island red crab, renowned for a yearly migration in which tens of millions of crabs scurry across the island to lay eggs in the ocean.

Lately, however, these crabs have been decimated by yellow crazy ants, an invasive species introduced to Christmas Island last century. The ants form supercolonies with billions of individuals, and their taste for red crabs poses a grave threat. Even crabs that live in areas without crazy ants are often killed during the annual trek, thus never returning to their off-season forests. The crabs play important roles in the island's unique ecosystems, so a population decline could trigger dangerous ripple effects.

Yet there's still hope. After years of trying to control the ants directly, researchers with Parks Australia and La Trobe University now hope to save the crabs by instead targeting a different invasive insect. And as Parks Australia explains in the animated video above, that involves releasing yet another non-native insect.

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