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Today 70 percent of the Earth’s surface is covered by water. These vast oceans were the world’s first battlegrounds, and they are still the largest. In this big blue battleground every creature - from the formidable Great White Shark to the tiny Blue Cleaner Wrasse - has its own array of weapons for finding prey or avoiding becoming prey themselves. An arsenal of gaping mouths with dagger-sharp teeth, knock-out punches and super speed give these animals an edge in the great underwater arms race.