For Part of one of my final year University modules about the representation of animals in film, I wrote some articles on some films with animals in, and they have been published on an online archive. Here they are:
The Plague Dogs - Dir. Martin Rosen. United Artists. 1982 : https://zooscope.english.shef.ac.uk/articles/66
The Selfish Giant - Dir. Clio Barnard. IFC Films. 2013 : https://zooscope.english.shef.ac.uk/articles/56
(there are also two shorter entries to come)