Problem Bake Normal Maps from hight poly mesh to low poly mesh I'm a student and this is my first experience with blender so I'm not an expert.
I'm facing a problem when I try to bake normals in tangent space. 

hippo.blend DOWNLOAD

I have two meshes representing an Hippo, created following some tutorials on youtube. One is high poly, second is low poly.



I'm using blender render, as in the tutorials.
I'm able to create an uv map unwrapping the low poly mesh and to do the first bake (select low poly mesh and click bake in render menu).


It is one day that I'm trying the final step of the tutorial in which I open my uv map in the uv editor, select in bake options "selection to active", I select the high poly mesh, shif+select low poly mesh and I click bake again. I can see that blender do the bake but the result does not change in any way.


I found the tutorials on youtube typing "Hippo Blender". They are five and I followed everything. But between the video 4 and video 5, I put bones and two animation on my model (not done in the original tutorial). Then I started again with the last tutorial.

I'm using blender 2.79b in the tutorial it is used blender 2.6 I think.
I try to read all the related topics in this forum but I'm not able to find a solution.

If someone can help me I can share the blender project

Thank you in advance

I edit the question after the answers adding some images of the current settings and the normals that I can see.






as you can see my uv map never changes.
in 3D View: you may have made a mistake in the scale, always keep in mind to apply scale CTRL + A select SCALE and ROTATION
play a little configuring the maximum distance and the minimum distance, until you get an optimal result or that you like
in edit mode, remember to apply the normal orientation of the faces towards the exterior, to check this you can turn on the normal indicator in  mesh display , select all and press CTRL + N
with respect to the Subdivision surface modifier, you can also play with the levels to see a result that you like, my example is done with this configuration


Blender Tutorial : Part 17 - Normal Mapping (Blender)