Posted by Harley on .
I just need to be sure that my personal explanation, from hands on research with sharks, of what causes tonic immobility makes sense.
What I found is that the only stimuli needed to induce tonic immobility on sharks, rays, and skates is slight compression on the Ampullae of Lorenzini (sensory organs in the snout) which naturally occurs when their jaw opens and the muscles in the jaw expand, compressing the Ampulae. I think this might occur as a survival strategy to keep the jaw from breaking and to keep the Ampulae safe. Though a sharks jaw exerts extremly high pressure, it is incredibly thin for its strength and breaks easily. If a shark were to go into tonic just before biting it would slow down just enough and be unaware of its surroundings for just long enough to avoid serious injury to its jaw, similar to a person in a coma, if they pass out and fall their injurys are almost always not as bad as a person who is aware of their surroundings and falls. I also saw from tests on shark's brains that just before they bite, their brain waves act as if they were in tonic. This is also more prevalent on sharks, rays, and skates that have higher than average anounts of ampullae such as hammerheads and lemon sharks.
Would this make sense to anyone who knows nothing about tonic immobility but has general knowledge about sharks.
Try some of the following links for verification:
That is the problem. No one knows exactly why or how tonic immobility happens. What I put in my first post is what I found from my own research with live sharks at a research facility. I need to include it in a report next Tuesday and I just need to make sure that it makes sense.