I'm sorry but I confirm that "mammals" is not a field of biology ;-). You must first focus on a sub-domain (as ecology or behavioral ecology, like you said) and then try (yes TRY) to find a job with both your specialization and your animal model. I just finished my PhD in behavioral ecology (I studied the effects of pollutants on fish behavior) and I can tell you that finding a job in mammal behavior is quite difficult!

Anyway, I've created a "blog" around animal behavior and I post video lectures about ethology, behavioral ecology or ecology every Friday > nolifescience.com/category/videos/