I found another reference photo of a crocodile, which I used to study the basic structure of the animal, in other words, what basic shapes we could use to construct a drawing of the beast ourselves, in a pose that is different from the reference photo. Before I could do that, I had to copy the pose in the reference photo, to discover how to draw a crocodile. I tried to learn by copying and analyzing.
After I knew how to build a basic crocodile shape, drawing a more realistic looking crocodile was a question of looking at the reference photo and trying to draw the features correctly and at the correct positions.
Well, I could have done it like I just described, but in reality, I did it a bit differently. I drew some of the basic shapes in pencil and started to draw the features even before I had all basic shapes on paper. This way it was easier for me to check for possible mistakes. If you look closely in the second sketch, you can spot where I drew the lines for the basic shapes.
I used a thin blue marker on the finished sketch to indicate the basic shapes I drew in pencil. I used the decompose into CMYK function in GIMP to separate the gray pencil markings from the blue marker lines. So that’s why I could present two separate drawings, which were actually drawn as one single drawing on paper. I used some computer magic to separate them out.
After having indicated the basic shapes with blue marker, I now know what those basic shapes are. So next time, I can draw the basic shapes first, and build the features on top.
As usually with animals, the head has the most details, and probably requires a separate study to get it right.
BTW If you want to know the basic 3D shape of a crocodile, think of a trapezium as a cross-section: parallel lines top and bottom, outward slanting lines at the sides, narrow at the top, broad at the base. This has to be an adaptation, so the animal can hide as much of its body mass under water. Also, the tail has two sections: a elongated tapering block and an elongated pyramid.
That is all.