The body language of sharks
On our first dive or snorkelling trip we saw a lot of sharks without understanding their behaviour. We could easily distinguish males from females by their claspers (in males, the pelvic fins have transformed into elongated genitals, while the females here have normal pelvic fins), but that was it more or less. It took Erich's lecture to open our eyes.
As the sharks swim towards us, we can already read a lot in their body language. The flapping frequency of their tail fins immediately indicates whether the shark is agitated or relaxed. If it’s already stopped moving its tail fin right in front of us in its last approach and is gliding, it is extremely relaxed. In order to avoid a collision with humans, it will turn off a few degrees to the left or right. The size of the angle gives another indication of its condition. The later and the less it turns, the less suspicious it is.
If the shark swims past us and we keep eye contact, the shark will also keep eye contact. If we now turn and swim with the shark, it will abandon its straight path and swim in an arch, so as not to lose eye contact. My interpretation: It’s feeling watched and does not want to turn its back on us. Better safe than sorry!
If a shark swims towards us and we turn our backs on it, it will evade us to a much slighter degree and will swim past us very closely. Again, this shows that the shark feels "safer" if we do not observe it.
The pectoral fin position will already tell us, which direction the shark swimming towards us, will turn off in. It lowers the pectoral fin at the side of the direction it will go in, like a paddle when it’s used to change the direction of a boat.
If we notice a shark's mouth, we’re probably looking at its teeth, but there is more to see: A slightly open mouth again indicates a relaxed shark. The closed mouth indicates tenseness.
We could now interpret an amazing amount of shark behaviour and body language of the sharks. All you need to open your eyes is an expert like Erich Ritter!