10 June, 2019
Dragonfish live deep down in the dark ocean, and are frightening-looking creatures.
Their sharp, transparent teeth help them survive in the hostile environment. The cause of their see-through teeth has long been a mystery. But scientists say they have an answer.
In the near-black deep water, a substance covering the teeth prevents any light from reflecting off the teeth surface. This helps a dragonfish hide their big teeth from creatures it wants to eat.
"The mouth is invisible and the prey is caught more easily," said scientist Marc Andre Meyers of the University of California, San Diego. He led the research, which was published this month in the journal Matter.
Dragonfish have teeth similar to humans and other animals. They are made up of an outer layer of enamel, and an inner layer of hard, dense, bony tissue called dentin. But in dragonfish, the material has been reorganized.
In the fish teeth enamel are extremely small crystals. And in the dentin, scientists found extremely small pieces of a protein called collagen. If such structures were larger, they would make light scatter. But because they are so small, light passes with ease. The teeth are also very thin.
Together, these differences prevent any light tha