Human and animal intelligence

[Stefano Gragnani]

I am a young physic's student with interest for this topic:
I would like some information about study and scientific researches on
human and animal intelligence, coscience, reasoning. For example: what
about the differences between bovines and equine? Are them measurable? I
would like qualified answers and, if it possible, some bibliography of
books that I could read on the subject. 

Thanks
Simona