When migrating red crabs march into their territory, the ants attack.

当迁徙的红蟹经过它们的领地时，黄疯蚁便展开攻击。

But in recent years, millions of red crabs haven't managed to reach the sea.

但近些年来数以百万的红蟹未能成功抵达海洋。

Twas five weeks before Christmas and all across that island, red crabs were traversing the lowlands and highlands.

现在离圣诞节还有五周，红蟹正在岛上的低地和高地穿行。

Even the famous red crabs on Australia's Christmas Island, which used to keep the island's undergrowth in check; without them, the ecosystem has veered into chaos.

甚至是澳大利亚圣诞岛上用来控制灌木丛生长的红螃蟹，没有了红蟹，生态系统已经陷入混乱。

Once a year, they must all return to the sea to breed, and the march of the red crabs is one of the greatest natural spectacles on earth.

每年它们都会回到海洋中进行繁殖，而红蟹大迁徙是地球是最伟大的自然奇观之一。