Nusrat Jahan
Moken, or otherwise known as Sea Gypsies of south-east Asia are a semi-nomadic Austronesian tribe, that lives in the Mergui Archipelago, a group of approximately 800 islands in the Andaman Sea that belongs to both Burma and Thailand. A few months back, Facebook was taken by storm as the video that gave us a sneak-peek into the fascinating lives of the peculiarly beautiful tribe of sea gypsies went viral. If you have not seen the video already then Google “BBC human planet sea gypsy video” right now! Otherwise (or not), keep reading!
The Moken children spend a lot of their day in the sea, in search of food. Hence, they are developed unique physical adaptations that allows them to see underwater! When the tides start coming in, the Moken children dive in to the sea to fetch food that lay metres below what an average human being could see, and they keep their eyes wide open the entire time. In 1999, Anna Gislen, a researcher from the University of Lund, in Sweden, visited the land (or should I say “water”) of the sea gypsies, and set up an experiment to test the strength of the Moken children’s underwater vision. The kids enthusiastically participated in the experiment as they thought it was some fun game.
When we are under water, we see things blurry, because we lose the refractive power of our cornea due to it having the same density as water. It is typical for our eyes to completely opt out of accommodating while we our under water since everything is so blurry. However, the Moken children are able to make their pupils smaller and change their lens shape, just like Seals and Dolphins. Gislen also tested a few Moken adults following the same method. They, however, could not show any atypical underwater accommodation, which is probably why they resort to spear fishing on the surface.
Anna Gislen then proceeded to speculate whether the Moken children had undergone some sort of genetic evolution which allowed them to see underwater or was it just because of how often they had to do it. To reach an answer, she asked a group of European and Swedish children to come for a holiday in Thailand, and tested them in the very same way she tested the Moken children. And guess what! After eleven practice sessions over a one month stay, these children attained the same abilities too. However, the European kids did experience red eyes and irritations caused by the salty sea-water, whereas the Moken children did not have any such difficulties. So who knows, maybe they have undergone some sort of evolution. The Moken kids sure know their way around the phrase “the survival of the fittest”!