Complex sentence: The Congo Basin subspecies demonstrates seasonality in its dietary regime, feeding on fish brought by the wet season's floods to their swampy habitat and when faced with the scarceness of food characteristic of the dry season individuals turn to crustaceans and food intake is generally reduced.
Split into simpler sentences: The Congo Basin subspecies demonstrates seasonality in its dietary regime, feeding on fish during the wet season's floods. When faced with the scarceness of food during the dry season, individuals turn to crustaceans and food intake is generally reduced.