RAM usage unusually high, but CPU usage relatively low

I’ve created a relatively simple game using libgdx, but the RAM usage when I start up the game on my Android device is roughly 600-700 mb, but the CPU usage is only about ~0.05%. I’ve downloaded a game which seems to use similar components to mine, and its RAM usage is only ~100-200mb.

I use an AssetManager to load all of my assets, which are fair in size (the largest asset I have is probably my main game theme song which is ~3mb; all other graphic assets are ~1-2mb).

Are there any tips for how I can reduce the RAM usage of my game?