As a child, we used to return to the city of Trichur, in Kerala, India every summer to stay with my grandparents. The Trichur(Trissur) zoo holds a special place in my heart and memories for two reasons, the crocodile that I would never see and the king cobra that would never move. I remember running to the crocodile pond and staring down into the green algae filled pond to see the crocodile each year but I never saw it. One summer, I fancied I saw a shoe floating in the water and imagined the poor soul to whom the show belonged to. The reason why I probably never saw the crocodile was because it was usually submerged under the green still water with only its eyes sticking out and from a height of 50 feet, it was hard to spot two dots in the murky green water. Twenty years later, scientists now in the Journal of Experimental Biology have found out conclusively that crocodiles can sleep with one eye open and by extension one half of their brain active while the other half sleeps.
Well, unless you live with immature room mates who like to walk in while you are sleeping as a prank, then you don’t really need to keep one eye open as the old adage goes. However, for animals, the cost of sleeping fully is a very steep one as they could fall prey to predators or on the other side of the equation, loose potential prey.
To understand how difficult this is, try, sleeping with your eyelids on one eye open. Yes, it is very difficult for us- Homo sapiens, keeping the eyelids open forcefully will cause our eyes to dry out without being able to blink.
Crocodiles can and they can actually regulate the amount of activity their open eye can process depending on the type of environment the paper says. Put a human in the vicinity and that one eye is more active while the other one sleeps, constantly keeping a vigilant ‘eye’ on the human threat. Why is this important to us? Well, for a neuroscientist, it tells us just how much the brain can adapt to help a species in its environment.
Yes, their brains cannot derive multivariable calculus equations like mine can, but hey, they can sleep with one eye open, a very cool adaption which makes them the king of their environment like I am in calculus class.
The king cobra, well thats another post about the conservation of energy in cold blooded reptiles, I swear, I thought it was made of rubber because it never moved.
Have a good day 🙂