Video: Leo on Bioluminescence

Beyond the reach of sunlight, thousands of feet below the surface of the ocean, some creatures create their own light known as "bioluminescence." Take a trip through the mind of Leo Smith, who asks questions about deep sea fish evolution. Patterns in diversity can offer clues to why fish have evolved so many ways of brightening up the deep sea. Some seem to use light to blend into their surroundings, others to lure prey out of the surroundings, or even to attract mates.