Underwater, speed and strategy are key to making the kill. Ocean hunters have aced the aquatic hunting games, but, even for the top players, things don't always go according to plan. Sometimes the odds are stacked against even the most successful marine predators, and often making the kill is not as easy as you think. How many failed attempts before our hunters hit the jackpot? We give the low-down on how tough it really is for ocean predators to score a meal.