The Galapagos Islands have been the cradle of evolution ever since Darwin's book "The Origin of Species". Some of the stranges creatures have evolved here. Washed up these barren volcanic islands by strong winds millions of years ago, the marine iguana has undergone the most amazing transformations. Once he was a normal lizard that fed on lush greenery on land, on Galapagos he conquered the ocean to be able to survive. Nowadays he is the only lizard in the world that feeds exclusively on seaweed and grazes it on long dives underwater. An adaptation to the lack of food on land. An unequaled success story and yet it looks like it will find a sudden end. In recent decades, the population of marine iguanas continues to decline. Today, they are considered endangered. Many theories about their increased mortality have been set by scientists. But so far they could not find a clear cause of death. An autopsy of 80 dead marine iguanas in 2013 had a striking result: The stomach contents consisted of undigested red and green algae. The animals seem to have died with their stomachs full. Also, a study of the sea water gave no results. Since the beginning of 2015, the authorities have once again intensified their educational efforts. Scientists and park rangers want to clarify the mystery of the disappearance of the marine iguanas in a large-scale investigation. There are four hot tracks that could lead to solving the mystery of the vanishing dragons of the Galapagos.