Private Life of a Cat
"Private Life of a Cat" on Google Video
"Alexander Hammid's intimate study of a female cat and the birth and maturation of her five kittens." Produced by Alexander Hammid and Maya Deren, 1947. Video in public domain available at Archive.org.
**
luckycee posted this and it is just so awesome that I have to re-post it. It's 22 minutes (with no sound - this is important to know, as I kept turning up the volume on my computer like an idiot) and worth watching.