Did you know?
.....that when the light lessens around winter time.....that many people are prone to SAD....seasonal affective disorder. The therapy is encouraging the addition of alot more artificial lighting to subdue the serotonin in our brain. Well sharks have a thingy. called a pineal gland. This is a very thin membrane on the top of their skulls .that actually allows light to filter directly into the sharks brain and increases the flow of melatonin and serotonin, not much different than what occurs to our brain from light fluctuations. However. I don't think sharks get depressed, they do however use the pineal gland. and the amount of light there is available to tell it about certain events in the course of the yr. As winter and light reduction approach.....this tells the shark to seek warmer waters etc....It also shows the shark when the light level is at a certain intake that it is time to mate.