He swims, hardly making a sound, reaching six miles per hour at times. His front legs provide propulsion, while his back legs steer. His low profile makes him seem like a floating sliver of ice. He checks the seal's position and takes 

 

wind direction into account to work out his final approach. As he closes in, he makes a clever move, diving deep beneath the ice floe. He emerges on the blind side of the seal. 

 

So far, so good.

 

He can hold his breath for minutes and calculate the seal's exact position. 

 

Slo-mo reveals just how close he got. His skills show a remarkable intelligence at work. He hunted in all three dimensions, making full use of the opportunities offered by water and ice.