I would wager that all omnivorous mammals gain and lose weight by the same mechanisms. Depending on how you look at it, you could extend that out to all mammals and maybe further. Differing endocrine profiles affect energy partitioning of course (which mostly tracks along gender lines in healthy individuals), but the underlying mechanisms involved in gaining or losing fat are the same.
Edit: Even with your edit, I would still say that a net gain in adiposity is the result of more FFA being esterified in adipocytes compared to how many are released and oxidized. This would apply to all animals and of course both genders.
Edit2: To clarify, I mean the net FFAs stored/released as viewed over time, since adipocytes have a huge amount of transmembrane flux that increases as they increase in size.
